bpo-40025: Require _generate_next_value_ to be defined before members (GH-19098)

require `_generate_next_value_` to be defined before members
diff --git a/Misc/ACKS b/Misc/ACKS
index 69865fe..d4ffc36 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1240,6 +1240,7 @@
 Grant Olson
 Furkan Onder
 Koray Oner
+Ethan Onstott
 Piet van Oostrum
 Tomas Oppelstrup
 Jason Orendorff