gh-106318: Add doctest role to str.rsplit() method

Author: adorilson

Doc/library/stdtypes.rst

@@ -2577,7 +2577,11 @@ expression support in the :mod:`re` module).
    Return a copy of the string with trailing characters removed.  The *chars*
    argument is a string specifying the set of characters to be removed.  If omitted
    or ``None``, the *chars* argument defaults to removing whitespace.  The *chars*
-   argument is not a suffix; rather, all combinations of its values are stripped::
+   argument is not a suffix; rather, all combinations of its values are stripped:
+
+   For example:
+
+   .. doctest::
 
       >>> '   spacious   '.rstrip()
       '   spacious'
@@ -2592,6 +2596,7 @@ expression support in the :mod:`re` module).
       >>> 'Monty Python'.removesuffix(' Python')
       'Monty'
 
+
 .. method:: str.split(sep=None, maxsplit=-1)
 
    Return a list of the words in the string, using *sep* as the delimiter