Add PR number to whatsnew

Author: aiudirog

doc/source/whatsnew/v1.3.3.rst

@@ -19,7 +19,7 @@ Fixed regressions
 - Fixed regression in :meth:`.GroupBy.agg` incorrectly raising in some cases (:issue:`42390`)
 - Fixed regression in :meth:`RangeIndex.where` and :meth:`RangeIndex.putmask` raising ``AssertionError`` when result did not represent a :class:`RangeIndex` (:issue:`43240`)
 - Fixed regression in :meth:`read_parquet` where the ``fastparquet`` engine would not work properly with fastparquet 0.7.0 (:issue:`43075`)
-- Fixed regression in :func:`is_list_like` where objects with ``__iter__`` set to ``None`` would be identified as iterable
+- Fixed regression in :func:`is_list_like` where objects with ``__iter__`` set to ``None`` would be identified as iterable (:issue:`43373`)
 
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