Restore the Oxford comma

Author: ambv

Doc/whatsnew/3.14.rst

@@ -541,7 +541,7 @@ asyncio
 * :mod:`asyncio` has new utility functions for introspecting and printing
   the program's call graph: :func:`asyncio.capture_call_graph` and
   :func:`asyncio.print_call_graph`.
-  (Contributed by Yury Selivanov, Pablo Galindo Salgado and Łukasz Langa
+  (Contributed by Yury Selivanov, Pablo Galindo Salgado, and Łukasz Langa
   in :gh:`91048`.)
 
 io