Fixed #21154 -- Updated TemplateResponse docs to better explain context.

.. class:: TemplateResponse()

   TemplateResponse is a subclass of

    ``TemplateResponse`` is a subclass of

    :class:`~django.template.response.SimpleTemplateResponse` that uses

    a :class:`~django.template.RequestContext` instead of

    a :class:`~django.template.Context`.

    ``context``

        A dictionary of values to add to the template context. By default,

        this is an empty dictionary. :class:`~django.template.Context` objects

        are also accepted as ``context`` values.

        are also accepted as ``context`` values. If you pass a

        :class:`~django.template.Context` instance or subclass, it will be used

        instead of creating a new :class:`~django.template.RequestContext`.

    ``status``

        The HTTP Status code for the response.