ruff

8d1efe96 - Add a new "Opening a PR" section to the contribution guide (#21298)

Add a new "Opening a PR" section to the contribution guide (#21298) Summary -- This PR adds a new section to CONTRIBUTING.md describing the expected contents of the PR summary and test plan, using the ecosystem report, and communicating the status of a PR. This seemed like a pretty good place to insert this in the document, at the end of the advice on preparing actual code changes, but I'm certainly open to other suggestions about both the content and placement. Test Plan -- Future PRs :) --------- Co-authored-by: Micha Reiser <micha@reiser.io>