fixup! BUG: Categorical constructor scalar categories

Author: TomAugspurger

doc/source/whatsnew/v0.21.0.txt

@@ -36,6 +36,8 @@ Backwards incompatible API changes
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 - Support has been dropped for Python 3.4 (:issue:`15251`)
+- The Categorical constructor no longer accepts a scalar for the ``categories`` keyword. (:issue:`16022`)
+
 
 .. _whatsnew_0210.api:
 
@@ -112,7 +114,6 @@ Numeric
 Categorical
 ^^^^^^^^^^^
 
-- The Categorical constructor no longer accepts a scalar for the ``categories`` keyword (:issue:`16022`)
 
 Other
 ^^^^^