Allow return type annotations to use their own parentheses (#6436)

## Summary

This PR modifies our logic for wrapping return type annotations.
Previously, we _always_ wrapped the annotation in parentheses if it
expanded; however, Black only exhibits this behavior when the function
parameters is empty (i.e., it doesn't and can't break). In other cases,
it uses the normal parenthesization rules, allowing nodes to bring their
own parentheses.

For example, given:

```python
def xxxxxxxxxxxxxxxxxxxxxxxxxxxx() -> Set[
    "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
]:
    ...

def xxxxxxxxxxxxxxxxxxxxxxxxxxxx(x) -> Set[
    "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
]:
    ...
```

Black will format as:

```python
def xxxxxxxxxxxxxxxxxxxxxxxxxxxx() -> (
    Set[
        "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
    ]
):
    ...


def xxxxxxxxxxxxxxxxxxxxxxxxxxxx(
    x,
) -> Set[
    "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
]:
    ...
```

Whereas, prior to this PR, Ruff would format as:

```python
def xxxxxxxxxxxxxxxxxxxxxxxxxxxx() -> (
    Set[
        "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
    ]
):
    ...


def xxxxxxxxxxxxxxxxxxxxxxxxxxxx(
    x,
) -> (
    Set[
        "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
    ]
):
    ...
```

Closes https://github.com/astral-sh/ruff/issues/6431.

## Test Plan

Before:

- `zulip`: 0.99702
- `django`: 0.99784
- `warehouse`: 0.99585
- `build`: 0.75623
- `transformers`: 0.99470
- `cpython`: 0.75988
- `typeshed`: 0.74853

After:

- `zulip`: 0.99724
- `django`: 0.99791
- `warehouse`: 0.99586
- `build`: 0.75623
- `transformers`: 0.99474
- `cpython`: 0.75956
- `typeshed`: 0.74857

crates/ruff_python_formatter/src/expression/mod.rs

@@ -183,25 +183,45 @@ impl Format<PyFormatContext<'_>> for MaybeParenthesizeExpression<'_> {
                     needs_parentheses
                 }
             }
-            Parenthesize::Optional | Parenthesize::IfBreaks => needs_parentheses,
+            Parenthesize::Optional
+            | Parenthesize::IfBreaks
+            | Parenthesize::IfBreaksOrIfRequired => needs_parentheses,
         };
 
         match needs_parentheses {
-            OptionalParentheses::Multiline if *parenthesize != Parenthesize::IfRequired => {
-                if can_omit_optional_parentheses(expression, f.context()) {
-                    optional_parentheses(&expression.format().with_options(Parentheses::Never))
-                        .fmt(f)
-                } else {
+            OptionalParentheses::Multiline => match parenthesize {
+                Parenthesize::IfBreaksOrIfRequired => {
                     parenthesize_if_expands(&expression.format().with_options(Parentheses::Never))
                         .fmt(f)
                 }
-            }
+                Parenthesize::IfRequired => {
+                    expression.format().with_options(Parentheses::Never).fmt(f)
+                }
+                Parenthesize::Optional | Parenthesize::IfBreaks => {
+                    if can_omit_optional_parentheses(expression, f.context()) {
+                        optional_parentheses(&expression.format().with_options(Parentheses::Never))
+                            .fmt(f)
+                    } else {
+                        parenthesize_if_expands(
+                            &expression.format().with_options(Parentheses::Never),
+                        )
+                        .fmt(f)
+                    }
+                }
+            },
+            OptionalParentheses::Never => match parenthesize {
+                Parenthesize::IfBreaksOrIfRequired => {
+                    parenthesize_if_expands(&expression.format().with_options(Parentheses::Never))
+                        .fmt(f)
+                }
+
+                Parenthesize::Optional | Parenthesize::IfBreaks | Parenthesize::IfRequired => {
+                    expression.format().with_options(Parentheses::Never).fmt(f)
+                }
+            },
             OptionalParentheses::Always => {
                 expression.format().with_options(Parentheses::Always).fmt(f)
             }
-            OptionalParentheses::Never | OptionalParentheses::Multiline => {
-                expression.format().with_options(Parentheses::Never).fmt(f)
-            }
         }
     }
 }