Draft for Black 2023 stable style

[JelleZijlstra]

This shouldn't be merged before 2023 (in case we want to do another 22.12 release) and shouldn't be merged until we have consensus in #3407. I'm opening it so I can evaluate the effect of the draft 2023 style without the obviously problematic bits.

Closes #3407

• Clean up comments.py preview mode
• Clean up preview in init.py
• clean up normalize_invisible_parens preview
• more in linegen.py
• annotation_parens
• empty_lines_before_class_or_def_with_leading_comments
• handle_trailing_commas_in_head
• normalize_docstring_quotes_and_prefixes_properly (unused)
• one_element_subscript
• remove_block_trailing_newline
• remove_redundant_parens
• skip_magic_trailing_comma_in_subscript

TODO:

• Finalize decisions on style
• Clean up tests
• Verify all known crashers in the preview style don't apply on this branch
• Write a changelog entry

[github-actions]

diff-shades reports zero changes comparing this PR (1c8d157) to main (226cbf0).

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What is this? | Workflow run | diff-shades documentation

[JelleZijlstra]

I ran this on our internal codebase and was pretty happy with the result. Most of the changes I saw were removing blank lines (#3035). This PR currently leaves #3044 and experimental string processing in preview.

I'll defer working on this PR more (e.g., getting tests to pass) until my other PRs from today are merged.

[JelleZijlstra]

CI is green now apart from diff-shades telling me I changed the stable style, which is expected since that's the point of this PR.

I think tomorrow I'll cut a 23.1a1 release off this branch.

[ichard26]

We're getting there. Just one more day and then 23.1.0 will be out.

PR looks good, although I think you can delete everything under this header. You might want to keep/move the "Improved empty line management" stuff to the stable docs though as subpoint 1 could surprise some people.

[Jackenmen]

Sounds like it should be named 23.2.0 ;)

[JelleZijlstra]

As long as it's still January in California when we release it I'm calling it 23.1.0 :)