bug 1461350: Update docstrings for customizations
bug 1461350: Update docstrings for customizations

Update the docstrings for locale functions taken from Django to more
accurately describe the behaviour and where it deviates from Django's
behaviour.

Elchi3/kuma,escattone/kuma,SphinxKnight/kuma,SphinxKnight/kuma,a2sheppy/kuma,mozilla/kuma,a2sheppy/kuma,mozilla/kuma,mozilla/kuma,escattone/kuma,mozilla/kuma,SphinxKnight/kuma,jwhitlock/kuma,Elchi3/kuma,jwhitlock/kuma,escattone/kuma,a2sheppy/kuma,SphinxKnight/kuma,Elchi3/kuma,a2sheppy/kuma,Elchi3/kuma,SphinxKnight/kuma,a2sheppy/kuma,SphinxKnight/kuma,Elchi3/kuma,jwhitlock/kuma,jwhitlock/kuma,jwhitlock/kuma,mozilla/kuma