Clarify what we have for now, that way when this is eventually
cleaned up we hopefully don't have to ask the same questions again.
This really needs to all be moved to loader.8 or loader.conf.8 or just
something centralized so everything points to that and people can search
just that instead of having to know about many different manuals and
search through them, or using man -K and grabbing a cup of coffee.
MFC after: immediately