DOC: updated categorical docstring (pandas-dev#29068)

Author: javad94

pandas/core/arrays/categorical.py

@@ -295,7 +295,7 @@ class Categorical(ExtensionArray, PandasObject):
 
     See Also
     --------
-    api.types.CategoricalDtype : Type for categorical data.
+    CategoricalDtype : Type for categorical data.
     CategoricalIndex : An Index with an underlying ``Categorical``.
 
     Notes