[Enum] add whatsnew entries (GH-95455)

Doc/whatsnew/3.11.rst

@@ -471,6 +471,49 @@ datetime
   formats (barring only those that support fractional hours and minutes).
   (Contributed by Paul Ganssle in :gh:`80010`.)
 
+enum
+----
+
+* ``EnumMeta`` renamed to ``EnumType`` (``EnumMeta`` kept as alias).
+
+* ``StrEnum`` added -- enum members are and must be strings.
+
+* ``ReprEnum`` added -- causes only the ``__repr__`` to be modified, not the
+  ``__str__`` nor the ``__format__``.
+
+* ``FlagBoundary`` added -- controls behavior when invalid values are given to
+  a flag.
+
+* ``EnumCheck`` added -- used by ``verify`` to ensure various constraints.
+
+* ``verify`` added -- function to ensure given ``EnumCheck`` constraints.
+
+* ``member`` added -- decorator to ensure given object is converted to an enum
+  member.
+
+* ``nonmember`` added -- decorator to ensure given object is not converted to
+  an enum member.
+
+* ``property`` added -- use instead of ``types.DynamicClassAttribute``.
+
+* ``global_enum`` added -- enum decorator to adjust ``__repr__`` and ``__str__``
+  to show members in the global context -- see ``re.RegexFlag`` for an example.
+
+* ``Flag`` enhancements: members support length,  iteration, and containment
+  checks.
+
+* ``Enum``/``Flag`` fixes: members are now defined before ``__init_subclass__``
+  is called; ``dir()`` now includes methods, etc., from mixed-in data types.
+
+* ``Flag`` fixes: only primary values (power of two) are considered canonical
+  while composite values (3, 6, 10, etc.) are considered aliases;  inverted
+  flags are coerced to their positive equivalent.
+
+* ``IntEnum`` / ``IntFlag`` / ``StrEnum`` fixes: these now inherit from
+  ``ReprEnum`` so the ``str()`` output now matches ``format()`` output,
+  which is the data types' (so both ``str(AnIntEnum.ONE)`` and
+  ``format(AnIntEnum.ONE)`` is equal to ``'1'``).
+
 fractions
 ---------