add description for bugfix in whatsnew and missing type hints in datetimelike _shallow_copy

Author: annika-rudolph

doc/source/whatsnew/v3.0.0.rst

@@ -412,7 +412,7 @@ Missing
 MultiIndex
 ^^^^^^^^^^
 - :func:`DataFrame.loc` with ``axis=0``  and :class:`MultiIndex` when setting a value adds extra columns (:issue:`58116`)
--
+- :func:`MultiIndex.get_level_values` accessing a :class:`DatetimeIndex` does not carry the frequency attribute along (:issue:`58327`, :issue:`57949`)
 
 I/O
 ^^^

pandas/core/indexes/datetimelike.py

@@ -844,9 +844,9 @@ def take(
         return result
 
     @doc(Index._shallow_copy)
-    def _shallow_copy( # type: ignore[override]
+    def _shallow_copy(  # type: ignore[override]
         self,
-        values,
+        values: np.ndarray,
         name: Hashable = no_default,
         level_codes=no_default,
     ) -> Self: