whatsnew update

Author: reidy-p

doc/source/whatsnew/v0.22.0.txt

@@ -24,7 +24,7 @@ Other Enhancements
 
 - Better support for :func:`Dataframe.style.to_excel` output with the ``xlsxwriter`` engine. (:issue:`16149`)
 - :func:`pandas.tseries.frequencies.to_offset` now accepts leading '+' signs e.g. '+1h'. (:issue:`18171`)
-- :func:`Series.fillna` now accepts a Series or a dict as a ``value`` (:issue:`17033`)
+- :func:`Series.fillna` now accepts a Series or a dict as a ``value`` for a categorical dtype (:issue:`17033`)
 
 .. _whatsnew_0220.api_breaking: