alphabetize 3.15 patch notes

Author: jyalim

Doc/library/datetime.rst

@@ -2676,7 +2676,7 @@ differences between platforms in handling of unsupported format specifiers.
    ``%:z`` was added for :meth:`~.datetime.strftime`.
 
 .. versionadded:: 3.15
-   ``%:z``, ``%F``, ``%D``, and ``%t`` were added for
+   ``%D``, ``%F``, ``%t``, and ``:%z`` were added for
    :meth:`~.datetime.strptime`.
 
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