fix: Remove parenthesis around sole list items

[cobaltt7]

Fixes #3545, but it affects more places as well.

Description

I added the remove_lone_list_item_parens preview style to remove parentheses around items in lists and sets that aren't accompanied by anything else. It's important to note that it depends on the unstable hug_parens_with_braces_and_square_brackets style to remove parentheses around multiline list items, such as the ones reported in #3545.

Checklist - did you ...

• [y] Add an entry in CHANGES.md if necessary?
• [y] Add / update tests if necessary?
• [y] Add new / update outdated documentation?

[github-actions]

diff-shades reports zero changes comparing this PR (8c4519f) to main (b677a64).

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

[JelleZijlstra]

Thanks, these changes look good.

However, I think I'd prefer to keep feature names stable through the year. The main motivation for adding --enable-unstable-feature was to allow users who want to keep some feature on to just turn on the feature in their config and have it keep working.

Also, I don't want to accept a PR that directly adds a new unstable style. I see the unstable style as a holding pen for style changes that we'd originally put into preview but later ran into issues with. New style features should go into preview instead.

[cobaltt7]

Apologies for the delay @JelleZijlstra, I've had other priorities recently.

The main issue was hug_parens_with_braces_and_square_brackets was required for the parens to be removed around multi-line expressions. I tried to identify exactly what parts it depended on, but I don't think it would be an easy refactor. I settled on just documenting this limitation instead.

I put remove_lone_list_item_parens in the unstable style due to this limitation, although it does work on its own for simple cases. If desired, I could move it to the preview style so preview users could get the benefits in those cases, or we could wait for hug_parens_with_braces_and_square_brackets. The original issue #3545 was for the more complex cases.

[cobaltt7]

Hey @JelleZijlstra just returned to this PR, sorry for letting it go stale

I removed this change from the unstable style, because it doesn't add any issues on its own, it just doesn't work in all cases without hug_parens_with_braces_and_square_brackets. I also resolved the conflicts.

Do these changes look good?

[JelleZijlstra]

Thank you!

[JelleZijlstra]

Maybe we should also extend this to single-element sets? The code should be very similar.

[cobaltt7]

@JelleZijlstra Done!