[1.6.x] Improved docs for GEOSGeometry.simplify()
[1.6.x] Improved docs for GEOSGeometry.simplify()

Backport of aa8bc7fa7d from master

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