Undo the change in categorical.rst

Author: jahn96

doc/source/user_guide/categorical.rst

@@ -1185,4 +1185,12 @@ Counting CategoricalDtype
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
 As mentioned in :ref:`Equality Semantics <categorical.equalitysemantics>`, two instances of :class:`~pandas.api.types.CategoricalDtype` compare equal
-whenever they have the same categories and order. Therefore, the multiple instances of :class:`~pandas.api.types.CategoricalDtype` will be counted as one group if they have the same categories and order.
+whenever they have the same categories and order. Therefore, when counting data types, the multiple instances of :class:`~pandas.api.types.CategoricalDtype` will be counted as one group if they have the same categories and order.
+In the example below, even though ``a``, ``c``, and ``d`` all have data types of ``category``, they will not be counted as one group since they don't have the same categories.
+
+.. ipython:: python
+
+    df = pd.DataFrame({'a': [1], 'b': ['2'], 'c': [3], 'd': [3]}).astype({'a': 'category', 'c': 'category', 'd': 'category'})
+    df
+    df.dtypes
+    df.dtypes.value_counts()