bpo-33018: Improve issubclass() error checking and message. (GH-5944)

This improves error message for situations when a non-class is
checked w.r.t. an abstract base class.
diff --git a/Misc/ACKS b/Misc/ACKS
index d752d8a..05932a8 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -202,6 +202,7 @@
 Richard Brodie
 Michael Broghton
 Ammar Brohi
+Josh Bronson
 Daniel Brotsky
 Jean Brouwers
 Gary S. Brown