Parenthesize singleton tuples in yield expressions

[wayyoungboy]

Fixes #3851.

Summary

• normalize yield expressions so bare singleton tuple yields like yield x, become yield (x,)
• preserve required parentheses around yield walrus expressions
• add a formatting fixture for singleton tuple yield expressions

Tests

• tests/test_format.py::test_simple_format[yield_singleton_tuple] (RED before fix)
• tests/test_format.py
• tests/test_black.py::BlackTestCase::test_get_features_used
• git diff --cached --check

[github-actions]

diff-shades results comparing this PR (85ccc76) to main (ce1897a):

--preview style (View full diff):

╭─────────────────────── Summary ────────────────────────╮
│ 2 projects & 6 files changed / 79 changes [+53/-26]    │
│                                                        │
│ ... out of 2 954 857 lines, 13 912 files & 22 projects │
╰────────────────────────────────────────────────────────╯
Differences found.

--stable style (View full diff):

╭─────────────────────── Summary ────────────────────────╮
│ 2 projects & 6 files changed / 79 changes [+53/-26]    │
│                                                        │
│ ... out of 2 954 857 lines, 13 912 files & 22 projects │
╰────────────────────────────────────────────────────────╯
Differences found.

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

[cobaltt7]

Thanks! This change affects more than just singleton yield tuples, it makes yield statements with any tuple behave more like functions in general, but I think this is a good change overall for consistency.

This changes Black's formatting, so it needs to be gated to the Preview style. See 01c29bd for a good recent example of how to do this. Please also add a changelog entry.

[wayyoungboy]

谢谢！这个变化不仅影响单元组，还让任何元组的语句更像函数，但我认为总体来说这是个好变化，有助于一致性。yield``yield

这改变了Black的格式，因此需要将它限制为预览样式。请参见01c29bd，那里有一个很好的近期示例。请同时添加更新日志条目。

Makes sense. I’ll move this behind preview style and add the changelog entry.

[wayyoungboy]

Updated.