Update CHANGES.md

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

Author: yilei

CHANGES.md

@@ -17,7 +17,7 @@
 - Add trailing commas to collection literals even if there's a comment after the last
   entry (#3393)
 - `async def`, `async for`, and `async with` statements are now formatted consistently
-  compared to their non-async version. #3609
+  compared to their non-async version. (#3609)
 - `with` statements that contain two context managers will be consistently wrapped in
   parentheses (#3589)