Fix user guide errors

Author: clbarnes

doc/source/user_guide/categorical.rst

@@ -130,13 +130,13 @@ This conversion is likewise done column by column:
     df_cat['B']
 
 Dummy / indicator / one-hot encoded variables
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Some operations, like regression and classification,
 encodes a single categorical variable as a column for each category,
 with each row having False in all but one column (True).
 These are called dummy variables, or one-hot encoding.
-:class:`pandas.Categorical`s can easily be converted to and from such an encoding:
+:class:`pandas.Categorical` objects can easily be converted to and from such an encoding:
 
 .. ipython:: python
 

doc/source/user_guide/reshaping.rst

@@ -666,8 +666,8 @@ To choose another dtype, use the ``dtype`` argument:
 .. versionadded:: 0.23.0
 
 For converting :class:`pandas.Categorical` objects directly
-to and from ``DataFrame``s of dummy variables, see
-:meth:`pandas.Categorical.to_dummies`and :meth:`pandas.Categorical.from_dummies`.
+to and from a ``DataFrame`` of dummy variables, see
+:meth:`pandas.Categorical.to_dummies` and :meth:`pandas.Categorical.from_dummies`.
 
 .. versionadded:: 1.1.0