Add support for Ruff as a code-formatter

[akaihola]

Fixes #521

• Review Add formatter command line and config option #568
• Merge Add formatter command line and config option #568
• Review Black as a plugin #738
• Merge Black as a plugin #738
• Review Speed up parameterized tests which use Git #761
• Merge Speed up parameterized tests which use Git #761
• Rebase on master
• Review Drop black dependency #759
• Merge Drop black dependency #759
• Rebase on master
• Review Separate module for Black imports #792
• Merge Separate module for Black imports #792
• Rebase on master

[akaihola]

FYI @clintonsteiner @mrfroggg @Svenito support for Ruff as a code re-formatter is soon landing. This branch basically works already, we just need to add tests and documentation and clean up a bit. After that, code reviews would be highly appreciated! I'll invite you as collaborators on the repository just in case you might have time to review.

[clintonsteiner]

Sounds great! Let me know what I can do to help

[clintonsteiner]

I'd be happy to review, add tests, or add docs. Thank you!

[clintonsteiner]

I have some changes - would like to help.
Would you prefer I make a pull request on top of this branch?

[akaihola]

Hi @clintonsteiner, thanks for your reply! I just rebased this branch on master, feel free to make your pull requests on top of this branch.

Note that there's a stack of branches sitting on top of each other, and I'm planning to merge them one by one and rebase the latter ones on master after merging:

• Add formatter command line and config option #568
  • branch `formatter-option'
• Black as a plugin #738
  • branch black-as-plugin
• Add support for Ruff as a code-formatter #744 (this PR)

If some of your fixes are about #568 or #738, it's ok for me if you still push them to a PR on top of #744. I can then do the clean-up work and move them up to the correct branch.

But reviewing #568 and #738 would certainly also help!

[clintonsteiner]

Left plenty of reviews, sorry just trying to be helpful
Feel free to ignore them as you disagree with them :)