[Enum docs]: fix order of arguments to isinstance() (GH-98542)

(cherry picked from commit 327fc1c6fa)

Co-authored-by: Clément Robert <cr52@protonmail.com>

Doc/library/enum.rst

@@ -434,7 +434,7 @@ Data Types
 
    .. note:: There are places in the stdlib that check for an exact :class:`str`
              instead of a :class:`str` subclass (i.e. ``type(unknown) == str``
-             instead of ``isinstance(str, unknown)``), and in those locations you
+             instead of ``isinstance(unknown, str)``), and in those locations you
              will need to use ``str(StrEnum.member)``.
 
    .. note::