CONTRIBUTING.md: update link for changelog fragments, and add more te…

…xt on them (#8322)

Update link for changelog fragments, and add more text on them.

CONTRIBUTING.md

@@ -31,7 +31,9 @@ Also, consider taking up a valuable, reviewed, but abandoned pull request which
 * Try committing your changes with an informative but short commit message.
 * Do not squash your commits and force-push to your branch if not needed. Reviews of your pull request are much easier with individual commits to comprehend the pull request history. All commits of your pull request branch will be squashed into one commit by GitHub upon merge.
 * Do not add merge commits to your PR. The bot will complain and you will have to rebase ([instructions for rebasing](https://docs.ansible.com/ansible/latest/dev_guide/developing_rebasing.html)) to remove them before your PR can be merged. To avoid that git automatically does merges during pulls, you can configure it to do rebases instead by running `git config pull.rebase true` inside the repository checkout.
-* Make sure your PR includes a [changelog fragment](https://docs.ansible.com/ansible/devel/community/development_process.html#creating-changelog-fragments). (You must not include a fragment for new modules or new plugins. Also you shouldn't include one for docs-only changes. If you're not sure, simply don't include one, we'll tell you whether one is needed or not :) )
+* Make sure your PR includes a [changelog fragment](https://docs.ansible.com/ansible/devel/community/collection_development_process.html#creating-a-changelog-fragment).
+  * You must not include a fragment for new modules or new plugins. Also you shouldn't include one for docs-only changes. (If you're not sure, simply don't include one, we'll tell you whether one is needed or not :) )
+  * Please always include a link to the pull request itself, and if the PR is about an issue, also a link to the issue. Also make sure the fragment ends with a period, and begins with a lower-case letter after `-`. (Again, if you don't do this, we'll add suggestions to fix it, so don't worry too much :) )
 * Avoid reformatting unrelated parts of the codebase in your PR. These types of changes will likely be requested for reversion, create additional work for reviewers, and may cause approval to be delayed.
 
 You can also read [our Quick-start development guide](https://github.com/ansible/community-docs/blob/main/create_pr_quick_start_guide.rst).