refactor(ruff): Implement doc_lines_from_tokens as iterator (#3124)

This is a nit refactor... It implements the extraction of document lines as an iterator instead of a Vector to avoid the extra allocation.

crates/ruff_cli/src/diagnostics.rs

@@ -81,7 +81,7 @@ pub fn lint_path(
     };
 
     // Read the file from disk.
-    let contents = fs::read_file(path)?;
+    let contents = std::fs::read_to_string(path)?;
 
     // Lint the file.
     let (