docs: Rename "private message" -> "direct message".

- Updates instances of "private message", "PM", and "private_message",
  excluding historical references in `overview/changelog.md`.
- Also excludes `/docs/translating` since we would need new
  translations for "direct messages" and "DMs".

CODE_OF_CONDUCT.md

@@ -136,7 +136,8 @@ Here are some guidelines for you how can help:
 
     I’ve gone ahead and moved the other copy of this message to this thread.
 
-  - If asked a question in a PM that is better discussed in a public stream:
+  - If asked a question in a direct message that is better discussed in a public
+    stream:
     > Hi @user! Please start by reviewing
     > https://zulip.com/development-community/#community-norms to learn how to
     > get help in this community.

docs/contributing/asking-great-questions.md

@@ -9,7 +9,7 @@ lifetime of fine-tuning. This page offers some guidelines and resources that the
 ## Where to ask your question
 
 It is almost always best to ask questions and have a conversation in a public
-stream, rather than in private messages. You’ll get better and faster answers
+stream, rather than in direct messages. You’ll get better and faster answers
 since many people can help, and it makes it possible for others to benefit from
 the discussion.
 

docs/contributing/code-reviewing.md

@@ -266,10 +266,10 @@ Some scenarios to consider:
 
 - Try clicking on any interactive elements, multiple times, in a variety of orders.
 - If the feature affects the **message view**, try it out in different types of
-  narrows: topic, stream, All messages, PMs.
+  narrows: topic, stream, All messages, direct messages.
 - If the feature affects the **compose box** in the web app, try both ways of
   [resizing the compose box](https://zulip.com/help/resize-the-compose-box).
-  Test both stream messages and PMs.
+  Test both stream messages and direct messages.
 - If the feature might require **elevated permissions**, check it out as a user who has
   permissions to use it and one who does not.
 - Think about how the feature might **interact with other features**, and try out
@@ -279,7 +279,7 @@ Some scenarios to consider:
   - If the feature has to do with topic editing, do you need to think
     about what happens when a topic is resolved/unresolved?
   - If it's a message view feature, would anything go wrong if the message was
-    collapsed or muted? If it was colored like an `@`-mention or a PM?
+    collapsed or muted? If it was colored like an `@`-mention or a direct message?
 
 ## Review process and communication
 

docs/contributing/how-we-communicate.md

@@ -101,7 +101,7 @@ to try something new.
 
 - You can use a variety of channels to express your appreciation. A comment
   directly in a Zulip thread or on a pull request is often best, but in some
-  cases you may also want to send a friendly PM. E.g.:
+  cases you may also want to send a friendly direct message. E.g.:
 
   - “I've noticed that you've been answering lots of questions in #**development
     help** lately. Thanks so much for doing that!”

docs/documentation/integrations.md

@@ -211,7 +211,7 @@ A typical doc will then have the following steps.
 ##### "Create the stream" step
 
 - Use the `create-stream` macro. This step should be omitted if the
-  integration only supports notifications via PMs.
+  integration only supports notifications via direct messages.
 
 ##### "Create the bot" step
 

docs/outreach/experience.md

@@ -171,7 +171,7 @@ system at the start of the program:
    review request
    feature](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/requesting-a-pull-request-review)
    to send your request. This makes the PR's status clear to project maintainers.
-   You may also want to send a quick private message to let your buddies know
+   You may also want to send a quick direct message to let your buddies know
    their attention is needed.
 
 4. Please respond to code review requests promptly (within one workday), and

docs/overview/architecture-overview.md

@@ -285,7 +285,7 @@ self-explanatory names.
   sidebar and users in right sidebar. To avoid visual clutter
   ellipsis only appears in the web UI upon hover.
 
-- **huddle**: What the codebase calls a "group private message".
+- **huddle**: What the codebase calls a "group direct message".
 
 - **message editing**: If the realm admin allows it, then after a user
   posts a message, the user has a few minutes to click "Edit" and
@@ -296,7 +296,7 @@ self-explanatory names.
 - **realm**: What the codebase calls an "organization" in the UI.
 
 - **recipient bar**: A visual indication of the context of a message
-  or group of messages, displaying the stream and topic or private
+  or group of messages, displaying the stream and topic or direct
   message recipient list, at the top of a group of messages. A
   typical 1-line message to a new recipient shows to the user as
   three lines of content: first the recipient bar, second the

docs/production/authentication-methods.md

@@ -65,7 +65,7 @@ In either configuration, you will need to do the following:
 
    - their **email address**. Zulip needs this in order to send, for
      example, a notification when they're offline and another user
-     sends a PM.
+     sends a direct message.
    - their **Zulip username**. This means the name the user types into the
      Zulip login form. You might choose for this to be the user's
      email address (`sam@example.com`), or look like a traditional

docs/production/mobile-push-notifications.md

@@ -67,8 +67,8 @@ following. Please follow the instructions carefully:
   need to log out first, since the app only registers for push
   notifications on login.
 - Hit the home button, so Zulip is running in the background, and then
-  have **another user** send you a **private message** (By default,
-  Zulip only sends push notifications for private messages sent by other
+  have **another user** send you a **direct message** (By default,
+  Zulip only sends push notifications for direct messages sent by other
   users and messages mentioning you). A push notification should appear
   in the Android notification area.
 
@@ -134,7 +134,7 @@ and privacy in mind:
   - The numeric message ID generated by your Zulip server.
   - Metadata on the message's sender (name and avatar URL).
   - Metadata on the message's recipient (stream name + ID, topic,
-    private message recipients, etc.).
+    direct message recipients, etc.).
   - A timestamp.
   - The message's content.
 

docs/production/security-model.md

@@ -148,11 +148,11 @@ strength allowed is controlled by two settings in
   organization.
 
   Being an organization administrator does not generally provide the ability
-  to read other users' private messages or messages sent to private
+  to read other users' direct messages or messages sent to private
   streams to which the administrator is not subscribed. There are two
   exceptions:
 
-  - Organization owners may get access to private messages via some types of
+  - Organization owners may get access to direct messages via some types of
     [data export](https://zulip.com/help/export-your-organization).
 
   - Administrators can change the ownership of a bot. If a bot is subscribed

docs/subsystems/events-system.md

@@ -69,11 +69,11 @@ Usually, this list of users is one of 3 things:
   like new realm emoji).
 - Everyone who would receive a given message (for messages, emoji
   reactions, message editing, etc.); i.e. the subscribers to a stream
-  or the people on a private message thread.
+  or the people on a direct message thread.
 
 It is the responsibility of the caller of `send_event` to choose the
 list of user IDs correctly. There can be security problems if e.g. an
-event containing private message content is sent to the entire
+event containing direct message content is sent to the entire
 organization. However, if an event isn't sent to enough clients,
 there will likely be user-visible real-time sync bugs.
 

docs/subsystems/hashchange-system.md

@@ -69,7 +69,7 @@ Internally you have these functions:
   a hash or using the back button) or triggered internally.
 - `hashchange.do_hashchange_normal` handles most cases, like loading the main
   page (but maybe with a specific URL if you are narrowed to a
-  stream or topic or PMs, etc.).
+  stream or topic or direct messages, etc.).
 - `hashchange.do_hashchange_overlay` handles overlay cases. Overlays have
   some minor complexity related to remembering the page from
   which the overlay was launched, as well as optimizing in-page

docs/subsystems/pointer.md

@@ -29,7 +29,7 @@ First a bit of terminology:
 ### Recipient bar: message you clicked
 
 If you enter a narrow by clicking on a message group's _recipient bar_
-(stream/topic or private message recipient list at the top of a group
+(stream/topic or direct message recipient list at the top of a group
 of messages), Zulip will select the message you clicked on. This
 provides a nice user experience where you get to see the stuff near
 what you clicked on, and in fact the message you clicked on stays at

docs/subsystems/sending-messages.md

@@ -317,7 +317,7 @@ not the total size of the community, then our database write limited
 send latency of 1 second per 2000 users is totally fine. But we need
 to do this in a way that doesn’t create problems if any of the
 thousands of “inactive” users come back (or one of the active users
-sends a private message to one of the inactive users), since it’s
+sends a direct message to one of the inactive users), since it’s
 impossible for the software to know which users are eventually coming
 back or will eventually be interacted with by an existing user.
 
@@ -390,6 +390,6 @@ There are a few details that require special care with this system:
 - Soft-deactivated users experience high loading latency when
   returning after being idle for months. We optimize this by
   triggering a soft reactivation for users who receive email or push
-  notification for private messages or personal mentions, or who
+  notification for direct messages or personal mentions, or who
   request a password reset, since these are good leading indicators
   that a user is likely to return to Zulip.

docs/subsystems/typing-indicators.md

@@ -12,7 +12,7 @@ system and possibly improve it. This document assumes that the
 client is our web app, but any client can play along with this
 protocol.
 
-Right now typing indicators are only used in "Private messages"
+Right now typing indicators are only used in "Direct messages"
 views.
 
 There are two major roles for users in this system:

docs/testing/manual-testing.md

@@ -57,12 +57,12 @@ Try narrowing from the message view:
   - use s to narrow to a stream (select message first
     and verify in sidebar)
   - use S to narrow to the topic (and verify in sidebar)
-  - use v to navigate to private messages
+  - use v to navigate to direct messages
 - Click on the recipient bar
   - narrow to a stream
   - narrow to a topic
-  - narrow to PMs with one user
-  - narrow to a group PM
+  - narrow to direct messages with one user
+  - narrow to a group direct message
 - Click on the Zulip logo
   - narrow to a topic
   - click on the Zulip logo (and verify you're in the Recent conversations view)
@@ -172,9 +172,9 @@ several times in a row, while cycling Cordelia through various narrows.
 Here are the main tasks for Hamlet (and each message gets sent several
 times):
 
-- Send Cordelia/Othello a PM.
-- Send Cordelia a PM.
-- Send Othello a PM.
+- Send Cordelia/Othello a direct message.
+- Send Cordelia a direct message.
+- Send Othello a direct message.
 - Post to Verona/foo.
 - Post to Verona/bar.
 - Post to Denmark/foo.
@@ -185,9 +185,9 @@ through the following views for Cordelia (and have Hamlet send new
 messages after each narrow):
 
 - Go to All messages view.
-- Go to Private messages view.
-- Go to Private messages w/Hamlet.
-- Go to Private messages w/Hamlet and Othello.
+- Go to Direct messages view.
+- Go to Direct messages w/Hamlet.
+- Go to Direct messages w/Hamlet and Othello.
 - Go to Verona view.
 - Go to Verona/bar view.
 - Go to Verona/foo view.
@@ -208,18 +208,18 @@ populated and where the focus is placed.
 - Hotkeys
 
   - use r to reply to a stream message
-  - use r to reply to a PM
-  - use R to reply to the author of a PM
-  - use R to reply to the author of a PM stream
+  - use r to reply to a direct message
+  - use R to reply to the author of a direct message
+  - use R to reply to the author of a direct message stream
   - use c to compose a stream message
-  - use x to compose a new PM
+  - use x to compose a new direct message
 
 - Buttons
 
   - Narrow to a stream and click on "New topic"
-  - Narrow "Private messages" and click on "New topic"
-  - Narrow to a stream and click on "New private message"
-  - Narrow "Private messages" and click on "New private message"
+  - Narrow "Direct messages" and click on "New topic"
+  - Narrow to a stream and click on "New direct message"
+  - Narrow "Direct messages" and click on "New direct message"
 
 - Topics
 
@@ -254,7 +254,7 @@ populated and where the focus is placed.
   - Use "restore drafts" to restore the draft.
   - Start composing a stream message and then abort using
     the little "x" icon in the compose box.
-  - Click on "New private message" and restore the draft. (You
+  - Click on "New direct message" and restore the draft. (You
     should now be sending to a stream.)
 
 - Click to send
@@ -296,9 +296,9 @@ Here are the things to test:
 
   - Verify email
   - Verify date message sent
-  - Send a PM (make sure compose box is filled out ok)
-  - Narrow to PMs with
-  - Narrow to PMs sent by
+  - Send a direct message (make sure compose box is filled out ok)
+  - Narrow to direct messages with
+  - Narrow to direct messages sent by
 
 - Right-pane-pane menus (click on chevron when hovering)
 
@@ -312,7 +312,7 @@ Here are the things to test:
   - Link to this conversation
 
 - Buddy list menus (click ellipsis when hovering over users)
-  - Narrow to PMs with
+  - Narrow to direct messages with
   - Narrow to message sent by
   - Compose a message to
 
@@ -408,8 +408,8 @@ Here are searches you should be able to do with autocomplete:
 - @-mentions
 - starred messages
 - messages sent by Hamlet
-- PMs with Hamlet
-- PMs with Hamlet matching keyword "foo"
+- direct messages with Hamlet
+- direct messages with Hamlet matching keyword "foo"
 
 There are some things you can try that don't come up in autocomplete:
 
@@ -497,12 +497,12 @@ Do these tasks as Cordelia.
       - have Hamlet send a message
       - then turn off notifications for that stream
       - have Hamlet send another message
-  - Private messages and @-mentions
+  - Direct messages and @-mentions
     - Test Desktop/Audible options
     - You can ignore other stuff for now
 - Bots/API key
-  - Create a bot with a generic avatar and send it a PM
-  - Create a bot with a custom avatar and send it a PM
+  - Create a bot with a generic avatar and send it a direct message
+  - Create a bot with a custom avatar and send it a direct message
   - Change your API key
 - Alert words
   - Create an alert word

docs/testing/testing-with-puppeteer.md

@@ -33,7 +33,7 @@ web app, like "Type this key", "Wait until this HTML element
 appears/disappears", or "Click on this HTML element".
 
 For example, this function might test the `x` keyboard shortcut to
-open the compose box for a new private message:
+open the compose box for a new direct message:
 
 ```js
 async function test_private_message_compose_shortcut(page) {