Become a CODEOWNER for typing (#31374)

diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index f484664..a884713 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -136,7 +136,7 @@
 
 **/*idlelib*                  @terryjreedy
 
-**/*typing*                   @gvanrossum @Fidget-Spinner
+**/*typing*                   @gvanrossum @Fidget-Spinner @JelleZijlstra
 
 **/*asyncore                  @giampaolo
 **/*asynchat                  @giampaolo