changes based on review

Author: charlesdong1991

doc/source/whatsnew/v0.25.0.rst

@@ -22,7 +22,7 @@ Other Enhancements
 - Indexing of ``DataFrame`` and ``Series`` now accepts zerodim ``np.ndarray`` (:issue:`24919`)
 - :meth:`Timestamp.replace` now supports the ``fold`` argument to disambiguate DST transition times (:issue:`25017`)
 - :meth:`DataFrame.at_time` and :meth:`Series.at_time` now support :meth:`datetime.time` objects with timezones (:issue:`24043`)
-- Add ``casefold`` to ``Series.str`` (:issue:`25405`)
+- ``Series.str`` has gained :meth:`Series.str.casefold` method to removes all case distinctions present in a string (:issue:`25405`)
 
 .. _whatsnew_0250.api_breaking:
 

pandas/core/strings.py

@@ -2944,6 +2944,7 @@ def rindex(self, sub, start=0, end=None):
     Series.str.swapcase : Converts uppercase to lowercase and lowercase to
         uppercase.
     Series.str.casefold: Removes all case distinctions in the string.
+        .. versionadded:: 0.25.0
 
     Examples
     --------