update whats new

Author: Hanspagh

doc/source/whatsnew/v1.1.3.rst

@@ -22,7 +22,7 @@ Fixed regressions
 
 Bug fixes
 ~~~~~~~~~
-- Bug in :meth:`isin()` when using NaN and a row length above 1,000,000 (:issue:`22205`)
+- Bug in :meth:`Series.isin` when using ``NaN`` and a row length above 1,000,000 (:issue:`22205`)
 
 .. ---------------------------------------------------------------------------