[1.6.x] Fix grammatical errors in email documentation
[1.6.x] Fix grammatical errors in email documentation

Backport of 43f213e475 from master

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