Remove comment lexing from isort (#6794)

## Summary

No need to lex to find comments -- we already know their locations via
`Indexer`.

crates/ruff_python_index/src/indexer.rs

@@ -99,18 +99,6 @@ impl Indexer {
         &self.comment_ranges
     }
 
-    /// Returns the comments in the given range as source code slices
-    pub fn comments_in_range<'a>(
-        &'a self,
-        range: TextRange,
-        locator: &'a Locator,
-    ) -> impl Iterator<Item = &'a str> {
-        self.comment_ranges
-            .comments_in_range(range)
-            .iter()
-            .map(move |comment_range| locator.slice(*comment_range))
-    }
-
     /// Returns the line start positions of continuations (backslash).
     pub fn continuation_line_starts(&self) -> &[TextSize] {
         &self.continuation_lines