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_formatter/src/buffer.rs

@@ -29,7 +29,6 @@ pub trait Buffer {
     ///
     /// assert_eq!(buffer.into_vec(), vec![FormatElement::StaticText { text: "test" }]);
     /// ```
-    ///
     fn write_element(&mut self, element: FormatElement) -> FormatResult<()>;
 
     /// Returns a slice containing all elements written into this buffer.