PEP 649: Fix my name (#4371)

Author: JelleZijlstra

peps/pep-0649.rst

@@ -1434,7 +1434,7 @@ Acknowledgements
 ****************
 
 Thanks to Carl Meyer, Barry Warsaw, Eric V. Smith,
-Mark Shannon, Jelle Ziljstra, and Guido van Rossum for ongoing
+Mark Shannon, Jelle Zijlstra, and Guido van Rossum for ongoing
 feedback and encouragement.
 
 Particular thanks to several individuals who contributed key ideas