Update v0.20.0.txt

Author: Joost Kranendonk

doc/source/whatsnew/v0.20.0.txt

@@ -23,7 +23,7 @@ New features
 ~~~~~~~~~~~~
 
 - Integration with the ``feather-format``, including a new top-level ``pd.read_feather()`` and ``DataFrame.to_feather()`` method, see :ref:`here <io.feather>`.
-- ``.str.replace`` now accepts a callable replacement which is passed to ``re.sub`` (:issue:`15055`)
+- ``.str.replace`` now accepts a callable, as replacement, which is passed to ``re.sub`` (:issue:`15055`)