Credit KowalskiThomas for bug analysis in NEWS entry

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: mvanhorn

Misc/NEWS.d/next/Library/2026-03-09-00-00-00.gh-issue-145492.457Afc.rst

@@ -1,2 +1,3 @@
 Fix infinite recursion in :class:`collections.defaultdict` ``__repr__``
-when a ``defaultdict`` contains itself.
+when a ``defaultdict`` contains itself. Based on analysis by KowalskiThomas
+in :issue:`145492`.