bpo-37479: on Enum subclasses with mixins, __format__ uses overridden __str__ (GH-14545)

* bpo-37479: on Enum subclasses with mixins, __format__ uses overridden __str__
diff --git a/Misc/ACKS b/Misc/ACKS
index a4d4372..36fe727 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -356,6 +356,7 @@
 Raúl Cumplido
 Antonio Cuni
 Brian Curtin
+Jason Curtis
 Paul Dagnelie
 Lisandro Dalcin
 Darren Dale