better col_offsets for "for" statements with tuple unpacking #6704

Patch from Frank Wierzbicki.
diff --git a/Misc/ACKS b/Misc/ACKS
index dc87dc2..79cde28 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -794,6 +794,7 @@
 Dik Winter
 Blake Winton
 Jean-Claude Wippler
+Frank Wierzbicki
 Lars Wirzenius
 Chris Withers
 Stefan Witzel