Fixes #13842: cannot pickle Ellipsis or NotImplemented.

Thanks for James Sanders for the bug report and the patch.
diff --git a/Misc/ACKS b/Misc/ACKS
index 49efa29..a0685c1 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -883,6 +883,7 @@
 Rich Salz
 Kevin Samborn
 Adrian Sampson
+James Sanders
 Ilya Sandler
 Mark Sapiro
 Ty Sarna