docs/style: Replace an example that uses a stream name that should be…

… an ID

The example was still valid for the point this section is making.
But there are lots of other examples to choose from, so pick one
that doesn't serve as a bad example in another respect.

docs/style.md

@@ -654,20 +654,20 @@ import * as api from '../api';
 
 // …
 
-    api.subscriptionAdd(auth, [{ name: stream.name }]);
+    const response = await api.uploadFile(auth, url, name);
 
 ```
 
 rather than like this:
 
 ```js
 // BAD
-import subscriptionAdd from '../api/subscriptions/subscriptionAdd';
+import uploadFile from '../api/uploadFile.js;
 
 // …
 
     // BAD
-    subscriptionAdd(auth, [{ name: stream.name }]);
+    const response = await uploadFile(auth, url, name);
 ```
 
 We do this because a lot of the names in our API bindings are also

src/api/subscriptions/subscriptionAdd.js

@@ -5,7 +5,6 @@ import { apiPost } from '../apiFetch';
 type SubscriptionObj = {|
   // TODO(server-future): This should use a stream ID (#3918), not stream name.
   //   Server issue: https://github.com/zulip/zulip/issues/10744
-  // TODO(#3918): Change example in docs/style.md to something without this issue.
   name: string,
 |};