Run rustfmt on nightly to clean up erroneous comments (#5106)

## Summary

This PR runs `rustfmt` with a few nightly options as a one-time fix to
catch some malformatted comments. I ended up just running with:

```toml
condense_wildcard_suffixes = true
edition = "2021"
max_width = 100
normalize_comments = true
normalize_doc_attributes = true
reorder_impl_items = true
unstable_features = true
use_field_init_shorthand = true
```

Since these all seem like reasonable things to fix, so may as well while
I'm here.

crates/ruff_python_formatter/src/comments/placement.rs

@@ -656,7 +656,7 @@ fn handle_positional_only_arguments_separator_comment<'a>(
 /// Handles comments between the left side and the operator of a binary expression (trailing comments of the left),
 /// and trailing end-of-line comments that are on the same line as the operator.
 ///
-///```python
+/// ```python
 /// a = (
 ///     5 # trailing left comment
 ///     + # trailing operator comment