Moved whatsnew to 0.24.0.

Author: victor

doc/source/whatsnew/v0.24.0.txt

@@ -662,8 +662,7 @@ Timedelta
 - Bug in :class:`Index` with numeric dtype when multiplying or dividing an array with dtype ``timedelta64`` (:issue:`22390`)
 - Bug in :class:`TimedeltaIndex` incorrectly allowing indexing with ``Timestamp`` object (:issue:`20464`)
 - Fixed bug where subtracting :class:`Timedelta` from an object-dtyped array would raise ``TypeError`` (:issue:`21980`)
--
--
+- Bug in :class:`Timedelta`: where passing a string of a pure number would not take unit into account. Also raises for ambiguous/duplicate unit specification (:issue: `12136`)
 
 Timezones
 ^^^^^^^^^