[1.6.x] Added some internal links to render_to_string documentation.
[1.6.x] Added some internal links to render_to_string documentation.

Backport of 1689744aee1f13b2f4e270ce63cea143eb6d868e from master.

redhat-openstack/django,redhat-openstack/django,django-nonrel/django,dex4er/django,dex4er/django,felixjimenez/django,django-nonrel/django,felixjimenez/django,felixjimenez/django,dex4er/django,felixjimenez/django,redhat-openstack/django,redhat-openstack/django,django-nonrel/django,django-nonrel/django