Reword parts of the "Policies" section (old uncommitted diff)
Start writing the "FreeBSD PAM Modules" section, which will provide
short descriptions of each of the PAM modules we ship in the base
system, along with recommendations about their use.

Note to translators: more to come in the very near future, so you may
wish to hold back on this one for a while.

Sponsored by: DARPA, NAI Labs