[DOCS] Django message references example breaks in version 1.11

[isms]

As of Django 1.11, django.Template.render() no longer accepts a Context object (changelog entry here).

Meanwhile, current example for adding message references to request context uses the old way:

    t = loader.get_template('500.html') # You need to create a 500.html template.
    return HttpResponseServerError(t.render(Context({
        'request': request,
    })))