Fixed whatsnew entry order.

Author: rosstitmarsh

doc/source/whatsnew/v2.1.0.rst

@@ -150,9 +150,9 @@ Timedelta
 ^^^^^^^^^
 - Bug in :meth:`Timedelta.round` with values close to the implementation bounds returning incorrect results instead of raising ``OutOfBoundsTimedelta`` (:issue:`51494`)
 - Bug in :class:`TimedeltaIndex` division or multiplication leading to ``.freq`` of "0 Days" instead of ``None`` (:issue:`51575`)
+- :meth:`arrays.TimedeltaArray.map` can now take a ``na_action`` argument. :meth:`TimedeltaIndex.map` with ``na_action="ignore"`` now works as expected. (:issue:`51644`)
 - Bug in constructing a :class:`Timedelta` with a valid ISO 8601 duration string raising an error (:issue:`51882`)
 - Bug in constructing a :class:`Timedelta` with an invalid ISO 8601 duration string not raising an error and returning unexpected values (:issue:`51882`)
-- :meth:`arrays.TimedeltaArray.map` can now take a ``na_action`` argument. :meth:`TimedeltaIndex.map` with ``na_action="ignore"`` now works as expected. (:issue:`51644`)
 - Bug in :meth:`arrays.TimedeltaArray.map` and :meth:`TimedeltaIndex.map`, where the supplied callable operated array-wise instead of element-wise (:issue:`51977`)
 -