Use shorter form of discuss URL

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>

Author: emmatyping

peps/pep-0784.rst

@@ -9,7 +9,7 @@ Created: 06-Apr-2025
 Python-Version: 3.14
 Post-History:
   `07-Apr-2025 <https://discuss.python.org/t/87377>`__,
-Resolution: `25-Apr-2025 <https://discuss.python.org/t/pep-784-adding-zstandard-to-the-standard-library/87377/138>`__
+Resolution: `25-Apr-2025 <https://discuss.python.org/t/87377/138>`__
 
 
 Abstract