Fix panic when formatting comments in unary expressions (#21501)

## Summary

This is another attempt at https://github.com/astral-sh/ruff/pull/21410
that fixes https://github.com/astral-sh/ruff/issues/19226.

@MichaReiser helped me get something working in a very helpful pairing
session. I pushed one additional commit moving the comments back from
leading comments to trailing comments, which I think retains more of the
input formatting.

I was inspired by Dylan's PR (#21185) to make one of these tables:

<table>
                <thead>
                    <tr>
                    <th scope="col">Input</th>
                    <th scope="col">Main</th>
                    <th scope="col">PR</th>
                    </tr>
                </thead>
                <tbody>
<tr>
<td><pre lang="python">
if (
    not
    # comment
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa +
bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
):
    pass
</pre></td>
<td><pre lang="python">
if (
    # comment
    not aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
    + bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
):
    pass

</pre></td>
<td><pre lang="python">
if (
    not
    # comment
    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
    + bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
):
    pass

</pre></td>
</tr>
<tr>
<td><pre lang="python">
if (
    # unary comment
    not
    # operand comment
    (
        # comment
        aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
        + bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
    )
):
    pass
</pre></td>
<td><pre lang="python">
if (
    # unary comment
    # operand comment
    not (
        # comment
        aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
        + bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
    )
):
    pass

</pre></td>
<td><pre lang="python">
if (
    # unary comment
    not
    # operand comment
    (
        # comment
        aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
        + bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
    )
):
    pass

</pre></td>
</tr>
<tr>
<td><pre lang="python">
if (
    not # comment
    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
    + bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
):
    pass
</pre></td>
<td><pre lang="python">
if (  # comment
    not aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
    + bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
):
    pass

</pre></td>
<td><pre lang="python">
if (
    not aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa  # comment
    + bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
):
    pass

</pre></td>
</tr>
</tbody>
            </table>

hopefully it helps even though the snippets are much wider here.

The two main differences are (1) that we now retain own-line comments
between the unary operator and its operand instead of moving these to
leading comments on the operator itself, and (2) that we move
end-of-line comments between the operator and operand to dangling
end-of-line comments on the operand (the last example in the table).

## Test Plan

Existing tests, plus new ones based on the issue. As I noted below, I
also ran the output from main on the unary.py file back through this
branch to check that we don't reformat code from main. This made me feel
a bit better about not preview-gating the changes in this PR.

```shell
> git show main:crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/unary.py | ruff format - | ./target/debug/ruff format --diff -
> echo $?
0
```

---------

Co-authored-by: Micha Reiser <micha@reiser.io>
Co-authored-by: Takayuki Maeda <takoyaki0316@gmail.com>

crates/ruff_python_formatter/src/comments/placement.rs

@@ -1890,9 +1890,11 @@ fn handle_lambda_comment<'a>(
     CommentPlacement::Default(comment)
 }
 
-/// Move comment between a unary op and its operand before the unary op by marking them as trailing.
+/// Move an end-of-line comment between a unary op and its operand after the operand by marking
+/// it as dangling.
 ///
 /// For example, given:
+///
 /// ```python
 /// (
 ///     not  # comment
@@ -1900,8 +1902,13 @@ fn handle_lambda_comment<'a>(
 /// )
 /// ```
 ///
-/// The `# comment` will be attached as a dangling comment on the enclosing node, to ensure that
-/// it remains on the same line as the operator.
+/// the `# comment` will be attached as a dangling comment on the unary op and formatted as:
+///
+/// ```python
+/// (
+///      not True  # comment
+/// )
+/// ```
 fn handle_unary_op_comment<'a>(
     comment: DecoratedComment<'a>,
     unary_op: &'a ast::ExprUnaryOp,
@@ -1923,8 +1930,8 @@ fn handle_unary_op_comment<'a>(
     let up_to = tokenizer
         .find(|token| token.kind == SimpleTokenKind::LParen)
         .map_or(unary_op.operand.start(), |lparen| lparen.start());
-    if comment.end() < up_to {
-        CommentPlacement::leading(unary_op, comment)
+    if comment.end() < up_to && comment.line_position().is_end_of_line() {
+        CommentPlacement::dangling(unary_op, comment)
     } else {
         CommentPlacement::Default(comment)
     }