Issue #16511: Use default IDLE width and height if config param is not valid.

Patch Serhiy Storchaka.
diff --git a/Misc/NEWS b/Misc/NEWS
index e7fa7d9..0c4b8b2 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -179,6 +179,9 @@
 Library
 -------
 
+- Issue #16511: Use default IDLE width and height if config param is not valid.
+  Patch Serhiy Storchaka.
+
 - Issue #16443: Add docstrings to regular expression match objects.
   Patch by Anton Kasyanov.