Moved whatsnew to 0.19.1 and clarified description

Author: Jon M. Mease

doc/source/whatsnew/v0.19.1.txt

@@ -54,6 +54,7 @@ Bug Fixes
 - Bug in ``MultiIndex.set_levels`` where illegal level values were still set after raising an error (:issue:`13754`)
 - Bug in ``DataFrame.to_json`` where ``lines=True`` and a value contained a ``}`` character (:issue:`14391`)
 - Bug in ``df.groupby`` causing an ``AttributeError`` when grouping a single index frame by a column and the index level (:issue`14327`)
+- Bug in ``df.groupby`` where ``TypeError`` raised when ``pd.Grouper(key=...)`` is passed in a list (:issue:`14334`)
 
 - Bug in ``pd.pivot_table`` may raise ``TypeError`` or ``ValueError`` when ``index`` or ``columns``
   is not scalar and ``values`` is not specified (:issue:`14380`)

doc/source/whatsnew/v0.20.0.txt

@@ -80,4 +80,3 @@ Performance Improvements
 
 Bug Fixes
 ~~~~~~~~~
-- Bug in ``df.groupby`` where ``TypeError`` raised when key-only Grouper is passed in a list (:issue:`14334`)