Fix #12811 by closing files promptly in tabnanny.check. Patch by Anthony Briggs.
diff --git a/Misc/ACKS b/Misc/ACKS
index 2b6104f..062a77a 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -121,6 +121,7 @@
 Brian Brazil
 Dave Brennan
 Tom Bridgman
+Anthony Briggs
 Tobias Brink
 Richard Brodie
 Michael Broghton