DOC: move release note

Author: TomAugspurger

doc/source/whatsnew/v0.20.2.txt

@@ -57,7 +57,6 @@ Conversion
 
 - Bug in :func:`to_numeric` in which empty data inputs were causing a segfault of the interpreter (:issue:`16302`)
 - Silence numpy warnings when broadcasting ``DataFrame`` to ``Series`` with comparison ops (:issue:`16378`, :issue:`16306`)
-- Bug in ``Series`` with ``dtype='category'`` (:issue:`16524`)
 
 
 Indexing

doc/source/whatsnew/v0.20.3.txt

@@ -44,6 +44,7 @@ Conversion
 ^^^^^^^^^^
 
 - Bug in pickle compat prior to the v0.20.x series, when ``UTC`` is a timezone in a Series/DataFrame/Index (:issue:`16608`)
+- Bug in ``Series`` with ``dtype='category'`` (:issue:`16524`)
 
 Indexing
 ^^^^^^^^