[CI] Remove unused variable in code-format job (llvm#165454)

`comments` were never used plus generated pylint error

Author: vbvictor

llvm/utils/git/code-format-helper.py

@@ -486,8 +486,6 @@ def hook_main():
         if fmt.has_tool():
             if not fmt.run(args.changed_files, args):
                 failed_fmts.append(fmt.name)
-            if fmt.comment:
-                comments.append(fmt.comment)
         else:
             print(f"Couldn't find {fmt.name}, can't check " + fmt.friendly_name.lower())