Avoid syntax error when formatting attribute expressions with outer parentheses, parenthesized value, and trailing comment on value

[dylwil3]

Closes #19350

I'm not sure if this is the expected/desired output. Without parentheses around the value, we have:

# unformatted
variable = (
    something # a comment
    .first_method("some string")
)

# formatted
variable = something.first_method("some string")  # a comment

It's a little unclear to me... it almost feels like in both cases (when something does or does not have parentheses) we should maintain the break, since that's what I would expect from a cursory reading of https://docs.astral.sh/ruff/formatter/black/#trailing-end-of-line-comments

[github-actions]

ruff-ecosystem results

Formatter (stable)

✅ ecosystem check detected no format changes.

Formatter (preview)

✅ ecosystem check detected no format changes.

[MichaReiser]

Thank you.

The comment placement is a bit weird if something isn't parenthesized, but the comment is very long:

variable = (
    (something) # a commentdddddddddddddddddddddddddddddd
    .first_method("some string")
)


variable = (
    something # a commentdddddddddddddddddddddddddddddd
    .first_method("some string")
)

Formatted

variable = (
    (something)  # a commentdddddddddddddddddddddddddddddd
    .first_method("some string")
)


variable = something.first_method(  # a commentdddddddddddddddddddddddddddddd
    "some string"
)

We might want to spent a little time to see if we can preserve the comment placement closer to where it used to be (by e.g. inserting a hard line break after the attribute name or using a line suffix boundary). But this might be harder than it looks and is something we could fix separately.

The fix otherwise looks good, e.g. it also fixes this code that previously produced invalid syntax (may be worth adding as a test to showcase that the issue isn't specific to assignment statements):

if (
    (something)  # a commentdddddddddddddddddddddddddddddd
    .first_method("some string")
): pass

[MichaReiser]

We'll now also use the new layout if value is parenthesized and has a trailing comment like this

variable = (
    (something # a comment  
    ).fist_method("some string")
)

I think that's fine but it might be worth adding a few more tests.

For example, this snippet now gets formatted differently:

if (
    (something # a comment  
    ).fist_method("some string") # second comment
): pass

Overall, maybe add a few more permutations with multiple comments (or at least play with it in the playground)

[MichaReiser]

Do we need to limit this to end of line comments only? Can you add a test where a value has both (unless that's not possible)

[dylwil3]

It's possible to have both (and we get a syntax error on main after formatting, but not in this PR). But you're right that we only need to use Multiline here if there's a trailing end of line comment, so I've narrowed the condition.

Added a test with both and a test just with trailing own-line comment (the latter formats with the same IR as on main, and without a syntax error, now that we narrowed the condition).

[dylwil3]

I've added some more tests, and I'm personally okay with the edge cases that produce slightly awkward formatting (in the name of getting rid of this syntax error). But let me know if you want me to try to tweak anything as part of this PR.

[MichaReiser]

Do we need to limit this to end of line comments only? Can you add a test where a value has both (unless that's not possible)