contributing docs: Update "Version Control" > "Commit discipline" links.

Updates `.html` links as a follow-up to #23750.

.github/pull_request_template.md

@@ -28,7 +28,7 @@ Communicate decisions, questions, and potential concerns.
 - [ ] Calls out remaining decisions and concerns.
 - [ ] Automated tests verify logic where appropriate.
 
-Individual commits are ready for review (see [commit discipline](https://zulip.readthedocs.io/en/latest/contributing/version-control.html)).
+Individual commits are ready for review (see [commit discipline](https://zulip.readthedocs.io/en/latest/contributing/commit-discipline.html)).
 
 - [ ] Each commit is a coherent idea.
 - [ ] Commit message(s) explain reasoning and motivation for changes.

CONTRIBUTING.md

@@ -343,7 +343,7 @@ labels.
 - **I think my PR is done, but it hasn't been merged yet. What's going on?**
   1. **Double-check that you have addressed all the feedback**, including any comments
      on [Git commit
-     discipline](https://zulip.readthedocs.io/en/latest/contributing/version-control.html#commit-discipline).
+     discipline](https://zulip.readthedocs.io/en/latest/contributing/commit-discipline.html).
   2. If all the feedback has been addressed, did you [leave a
      comment](#how-to-help-move-the-review-process-forward)
      explaining that you have done so and **requesting another review**? If not,
@@ -372,7 +372,7 @@ experience, these are the best predictors of success:
   you got stuck. Post tracebacks or other error messages if appropriate. For
   more advice, check out [our guide][great-questions]!
 - Learning and practicing
-  [Git commit discipline](https://zulip.readthedocs.io/en/latest/contributing/version-control.html#commit-discipline).
+  [Git commit discipline](https://zulip.readthedocs.io/en/latest/contributing/commit-discipline.html).
 - Submitting carefully tested code. See our [detailed guide on how to review
   code](https://zulip.readthedocs.io/en/latest/contributing/code-reviewing.html#how-to-review-code)
   (yours or someone else's).

templates/zerver/api/incoming-webhooks-walkthrough.md

@@ -477,7 +477,7 @@ request:
    through your code to double-check that you've followed Zulip's guidelines.
 3. Take a look at your Git history to ensure your commits have been clear and
    logical (see [Commit discipline](
-   https://zulip.readthedocs.io/en/latest/contributing/version-control.html) for tips). If not,
+   https://zulip.readthedocs.io/en/latest/contributing/commit-discipline.html) for tips). If not,
    consider revising them with `git rebase --interactive`. For most incoming webhooks,
    you'll want to squash your changes into a single commit and include a good,
    clear commit message.