Fixed #22242 -- Documented common cookie size limit.

    .. _HTTPOnly: https://www.owasp.org/index.php/HTTPOnly

    .. warning::

        Both :rfc:`2109` and :rfc:`6265` state that user agents should support

        cookies of at least 4096 bytes. For many browsers this is also the

        maximum size. Django will not raise an exception if there's an attempt

        to store a cookie of more than 4096 bytes, but many browsers will not

        set the cookie correctly.

.. method:: HttpResponse.set_signed_cookie(key, value, salt='', max_age=None, expires=None, path='/', domain=None, secure=None, httponly=True)

    Like :meth:`~HttpResponse.set_cookie()`, but