more doc fixes

Author: jreback

doc/source/whatsnew/v0.20.0.txt

@@ -600,7 +600,7 @@ pd.unique will now be consistent with extension types
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 In prior versions, using ``Series.unique()`` and ``pd.unique(Series)`` on ``Categorical`` and tz-aware
-datatypes would yield different return types. These are now made consistent.
+datatypes would yield different return types. These are now made consistent. (:issue:`15903`)
 
 - Datetime tz-aware
 
@@ -1215,7 +1215,6 @@ Conversion
 - Bug in ``.asfreq()``, where frequency was not set for empty ``Series`` (:issue:`14320`)
 - Bug in ``DataFrame`` construction with nulls and datetimes in a list-like (:issue:`15869`)
 - Bug in ``DataFrame.fillna()`` with tz-aware datetimes (:issue:`15855`)
-- Bug in the return type of ``pd.unique`` on a ``Categorical``, which was returning an ndarray and not a ``Categorical`` (:issue:`15903`)
 
 Indexing
 ^^^^^^^^