Refs #24987 -- Documented that Client.login() rejects inactive users.

        ``login()`` method to simulate the effect of a user logging into the

        site.

        Inactive users (:attr:`is_active=False

        <django.contrib.auth.models.User.is_active>`) are not permitted to

        login as this method is meant to be equivalent to the

        :func:`~django.contrib.auth.login` view which uses

        :class:`~django.contrib.auth.forms.AuthenticationForm` and therefore

        defaults to rejecting users who are inactive.

        After you call this method, the test client will have all the cookies

        and session data required to pass any login-based tests that may form

        part of a view.