Fix #12811 by closing files promptly in tabnanny.check. Patch by Anthony Briggs.
diff --git a/Misc/NEWS b/Misc/NEWS
index ab70dfd..eeb0d71 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -265,6 +265,9 @@
 Library
 -------
 
+- Issue #12811: tabnanny.check() now promptly closes checked files. Patch by
+  Anthony Briggs.
+
 - Issue #6560: The sendmsg/recvmsg API is now exposed by the socket module
   when provided by the underlying platform, supporting processing of
   ancillary data in pure Python code.