PEP 800: Add Discussions-To link (#4508)

Co-authored-by: Adam Turner <[email protected]>

Author: hugovk

peps/pep-0800.rst

@@ -1,7 +1,7 @@
 PEP: 800
 Title: Solid bases in the type system
 Author: Jelle Zijlstra <[email protected]>
-Discussions-To: Pending
+Discussions-To: https://discuss.python.org/t/99910/
 Status: Draft
 Type: Standards Track
 Topic: Typing