fix indentation of line breaks in long type hints by adding parens

[jakkdl]

Description

The simple way of resolving #2316
I would personally prefer to resolve it by formatting it without added parentheses (i.e. option 3 in #2316) to save two unnecessary lines, but that will likely require a bunch of messing around in _maybe_split_omitting_optional_parens and could also impact some other cases - so I think I'll hold off on that one for the moment.

I had to extend maybe_make_parens_invisible_in_atom to also allow expressions, I was quite afraid this would have side effects elsewhere in the code - but it seems to be fine? I could be defensive and add a parameter that enables checking syms.expr, and only set it when called from visit_tname.

There's minor changes to two existing test cases, but they both seem fine to me.

Checklist - did you ...

• Add an entry in CHANGES.md if necessary? [TODO]
• Add / update tests if necessary?
• Add new / update outdated documentation? [I don't think this needs to be done]

[JelleZijlstra]

Thanks. This looks generally good, but we'll want to make the change only in the preview style for now. Look for existing code like if Preview.parenthesize_conditional_expressions in self.mode: for examples.

[github-actions]

diff-shades results comparing this PR (391a413) to main (e974fc3). The full diff is available in the logs under the "Generate HTML diff report" step.

╭──────────────────────── Summary ────────────────────────╮
│ 3 projects & 15 files changed / 279 changes [+138/-141] │
│                                                         │
│ ... out of 2 489 089 lines, 11 731 files & 23 projects  │
╰─────────────────────────────────────────────────────────╯

Differences found.

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

[jakkdl]

Thanks. This looks generally good, but we'll want to make the change only in the preview style for now. Look for existing code like if Preview.parenthesize_conditional_expressions in self.mode: for examples.

Thanks, fixed!

[JelleZijlstra]

Looking at the diff-shades output, all changes seem like improvements: https://github.com/psf/black/actions/runs/6275527706/job/17044773640#step:10:1