Convert .buildkite to ruff format

[hmellor]

If we are converting directory x:

• In x, we add a local pyproject.toml which:
  • overrides isort to use the black profile
  • overrides ruff's line length to 88 (it's own default)
  • removes the deprecated type ignores
  • enables formatting of code in docstrings (good for the API docs)
• We add x to the list of files to run ruff-format on in .pre-commit-config.yaml
• We add x to the list of ignores in the yapf config in the root pyproject.toml

[github-actions]

👋 Hi! Thank you for contributing to the vLLM project.

💬 Join our developer Slack at https://slack.vllm.ai to discuss your PR in #pr-reviews, coordinate on features in #feat- channels, or join special interest groups in #sig- channels.

Just a reminder: PRs would not trigger full CI run by default. Instead, it would only run fastcheck CI which starts running only a small and essential subset of CI tests to quickly catch errors. You can run other CI tests on top of those by going to your fastcheck build on Buildkite UI (linked in the PR checks section) and unblock them. If you do not have permission to unblock, ping simon-mo or khluu to add you in our Buildkite org.

Once the PR is approved and ready to go, your PR reviewer(s) can run CI to test the changes comprehensively before merging.

To run CI, PR reviewers can either: Add ready label to the PR or enable auto-merge.

🚀

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @hmellor.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[simon-mo]

How does this work for PR touching conflicting files? Is there a process for PR author to conduct a smooth rebase?

[hmellor]

I would probably recommend that they run ruff format on the affected files in their PR.

Then, when they rebase, both sides of the diff will be ruff format and git will have a better time applying the PR on the new main.

[DarkLight1337]

More than one week has passed since the RFC #17657 so let's start!