Format trailing operator comments as dangling (#7427)

## Summary

Given a trailing operator comment in a unary expression, like:

```python
if (
  not  # comment
  a):
    ...
```

We were attaching these to the operand (`a`), but formatting them in the
unary operator via special handling. Parents shouldn't format the
comments of their children, so this instead attaches them as dangling
comments on the unary expression. (No intended change in formatting.)

crates/ruff_python_formatter/tests/snapshots/format@expression__unary.py.snap

@@ -152,6 +152,11 @@ if (
   # comment
   a):
     ...
+
+if (
+  not  # comment
+  a):
+    ...
 ```
 
 ## Output
@@ -317,6 +322,11 @@ if (
     a
 ):
     ...
+
+if (
+    not a  # comment
+):
+    ...
 ```