Fixed #17035, #17036 -- Clarified documentation regarding TemplateResponse and...

.. class:: HttpResponseServerError

    Acts just like :class:`HttpResponse` but uses a 500 status code.

.. note::

    If a custom subclass of :class:`HttpResponse` implements a ``render``

    method, Django will treat it as emulating a

    :class:`~django.template.response.SimpleTemplateResponse`, and the

    ``render`` method must itself return a valid response object.

.. method:: SimpleTemplateResponse.render():

    Sets :attr:`response.content` to the result obtained by

    :attr:`SimpleTemplateResponse.rendered_content`.

    :attr:`SimpleTemplateResponse.rendered_content`, runs all post-rendering

    callbacks, and returns the resulting response object.

    :meth:`~SimpleTemplateResponse.render()` will only have an effect

    the first time it is called. On subsequent calls, it will return

.. method:: process_template_response(self, request, response)

``request`` is an :class:`~django.http.HttpRequest` object. ``response`` is the

:class:`~django.template.response.SimpleTemplateResponse` subclass (e.g.

:class:`~django.template.response.TemplateResponse`) object returned by a

Django view.

``process_template_response()`` must return an

:class:`~django.template.response.SimpleTemplateResponse` (or its subclass)

object. It could alter the given ``response`` by changing

``response.template_name`` and ``response.context_data``, or it could

create and return a brand-new

:class:`~django.template.response.SimpleTemplateResponse` (or its subclass)

instance.

``request`` is an :class:`~django.http.HttpRequest` object. ``response`` is a

subclass of :class:`~django.template.response.SimpleTemplateResponse` (e.g.

:class:`~django.template.response.TemplateResponse`) or any response object

that implements a ``render`` method.

``process_template_response()`` must return a response object that implements a

``render`` method. It could alter the given ``response`` by changing

``response.template_name`` and ``response.context_data``, or it could create

and return a brand-new

:class:`~django.template.response.SimpleTemplateResponse` or equivalent.

``process_template_response()`` will only be called if the response

instance has a ``render()`` method, indicating that it is a

:class:`~django.template.response.TemplateResponse`.

:class:`~django.template.response.TemplateResponse` or equivalent.

You don't need to explicitly render responses -- responses will be

automatically rendered once all template response middleware has been