chore(issue templ): add "self service" section in templates

.github/ISSUE_TEMPLATE/bug.md

@@ -25,7 +25,7 @@ labels: 'bug, needs triage'
 
 <!--
 IMPORTANT: Please check the following items before creating a issue.
-Mark the checkbox by putting an X between the bracket.
+Mark the checkbox by replacing the space between the brackets with an X (- [X]).
 This way we know you've done these steps first.
 -->
 
@@ -47,11 +47,11 @@ This way we know you've done these steps first.
 
 Use https://new.docusaurus.io to create a CodeSandbox reproducible demo of the bug.
 
-(Write your steps here:)
+(Write your steps here.)
 
 1. Step 1...
-1. Step 2...
-1. Step 3...
+2. Step 2...
+3. Step 3...
 
 ## Expected behavior
 
@@ -70,8 +70,8 @@ Use https://new.docusaurus.io to create a CodeSandbox reproducible demo of the b
   Is something broken, or not behaving as you expected?
   Describe this section in detail, and attach screenshots if possible.
   Don't only say "it doesn't work"!
-  Please submit exhaustive and complete log messages (we also need the error strack-traces, not just the message).
-  Please read error messages carefully: it often tells you exactly what you are doing wrong
+  Please submit exhaustive and complete log messages (we also need the error stack-traces, not just the message).
+  Please read error messages carefully: it often tells you exactly what you are doing wrong.
 -->
 
 (Write what happened. Add full console log messages and screenshots, if applicable.)
@@ -107,3 +107,13 @@ Use https://new.docusaurus.io to create a CodeSandbox reproducible demo of the b
 
   Thanks for helping us help you!
 -->
+
+### Self-service
+
+<!--
+  If you feel like you could contribute to this issue, please check the box below by replacing the space with an X (- [X]).
+  This would tell us and other people looking for contributions that someone's working on it.
+  If you do check this box, please send a pull request within 7 days so we can still delegate this to someone else.
+-->
+
+- [ ] I'd be willing to fix this bug myself.

.github/ISSUE_TEMPLATE/documentation.md

@@ -4,10 +4,37 @@ about: Report an issue related to documentation
 labels: 'documentation, needs triage'
 ---
 
+<!--
+  This template is strictly used for documentation requests, including:
+  - Documenting undocumented APIs;
+  - Elaborating on a particular topic;
+  - Updating external links
+  - ...
+  i.e. anything that doesn't require touching the codebase itself.
+  If you followed the documentation but things don't work, take some time to consider if it's the documentation or the code that's wrong. In the latter, prefer using the "bug" template.
+
+  We seldom close documentation pull requests unmerged. If your documentation request is:
+  - Relevant to a significant proportion of Docusaurus users;
+  - Not about external tooling (e.g. deployment workflow. We have a "deployment" section but we have decided to keep it mostly as-is);
+  - Not documented elsewhere (or, if it is documented, the mention is in very undiscoverable places),
+  You may proceed directly to sending a pull request without filing this issue, and we can improve on your work.
+  If you think some of the requirements above are not met, or if you are not able to contribute yourself, the issue is still welcomed.
+-->
+
 ## 📚 Documentation
 
 (A clear and concise description of what the issue is.)
 
 ### Have you read the [Contributing Guidelines on issues](https://github.com/facebook/docusaurus/blob/master/CONTRIBUTING.md#reporting-new-issues)?
 
 (Write your answer here.)
+
+### Self-service
+
+<!--
+  If you feel like you could contribute to this issue, please check the box below by replacing the space with an X (- [X]).
+  This would tell us and other people looking for contributions that someone's working on it.
+  If you do check this box, please send a pull request within 7 days so we can still delegate this to someone else.
+-->
+
+- [ ] I'd be willing to address this documentation request myself.

.github/ISSUE_TEMPLATE/feature.md

@@ -8,7 +8,7 @@ labels: 'feature, needs triage'
   IMPORTANT:
   - We expect you to submit a feature request including a real design (API / UI...), not just a basic idea
   - The design does not have to be perfect, we'll discuss it and fix it if needed
-  - For a more "casual" feature requests, consider using Canny instead: https://docusaurus.io/feature-requests
+  - For a more "casual" feature request, consider using Canny instead: https://docusaurus.io/feature-requests
 -->
 
 ## 🚀 Feature
@@ -25,7 +25,7 @@ labels: 'feature, needs triage'
 
 ## Motivation
 
-(Please outline the motivation for the proposal and why it should be implemented. Has this been requested by a lot of users on our )
+(Please outline the motivation for the proposal and why it should be implemented. Has this been requested by a lot of users?)
 
 ## API Design
 
@@ -37,7 +37,7 @@ labels: 'feature, needs triage'
 -->
 
 <!--
-  What happens if you skip this step? This issue will be automatically closed.
+  What happens if you skip this step? This issue may be closed without any in-depth discussion.
   Your feature request is just an idea for now, please use Canny for that: https://docusaurus.io/feature-requests
 -->
 
@@ -55,3 +55,15 @@ labels: 'feature, needs triage'
   If you can't build it yourself for technical reasons, please explain why.
   We are willing to help you, and eventually providing new APIs to make it possible.
 -->
+
+### Self-service
+
+<!--
+  If you answered the question above as "no" because you feel like you could contribute directly to our repo, please check the box below by replacing the space with an X (- [X]).
+  This would tell us and other people looking for contributions that someone's working on it.
+  If you do check this box, please send a pull request within 7 days after a maintainer's approval so we can still delegate this to someone else.
+
+  Note that for feature issues, we still require you to fully fill out this form and reach consensus with the maintainers on API design before rushing to implement it, so that you don't waste your time.
+-->
+
+- [ ] I'd be willing to contribute this feature to Docusaurus myself.

.github/ISSUE_TEMPLATE/proposal.md

@@ -5,8 +5,16 @@ labels: 'proposal, needs triage'
 ---
 
 <!--
-  This is not for feature requests.
-  Consider requesting the feature on https://docusaurus.io/feature-requests instead.
+  Common reasons for proposals include:
+  - Altering the infrastructure (e.g. swapping Webpack out with other bundlers);
+  - Bumping a critical dependency's major version;
+  - A significant improvement to a CLI command;
+  - Significant refactor;
+  - ...
+
+  This is not for feature requests. If this involves new APIs or new behaviors, consider requesting the feature on https://docusaurus.io/feature-requests instead.
+  We give you maximum freedom to write an elaborated proposal illustrating why you think the change is beneficial for us, and what steps we should take to turn this into reality.
+  You should not use this to ditch the feature request or bug template; such action could make us identify the issue wrongly and close it without doing anything.
 -->
 
 ## 💥 Proposal
@@ -16,3 +24,15 @@ labels: 'proposal, needs triage'
 ### Have you read the [Contributing Guidelines on issues](https://github.com/facebook/docusaurus/blob/master/CONTRIBUTING.md#reporting-new-issues)?
 
 (Write your answer here.)
+
+### Self-service
+
+<!--
+  If you feel like you could contribute to this issue, please check the box below by replacing the space with an X (- [X]).
+  This would tell us and other people looking for contributions that someone's working on it.
+  If you do check this box, please send a pull request within 7 days after a maintainer's approval so we can still delegate this to someone else.
+
+  Proposals usually involve significant code changes, so please reach consensus with the maintainers before rushing to implement it. This ensures that you don't waste your time and we don't waste ours reading the large diffs.
+-->
+
+- [ ] I'd be willing to do some initial work on this proposal myself.