[arch-general] rc.conf man page

[Martín Cigorraga]

@Dave

I readed your man page draft and it's quite useful - to me, a simple
end-user.
About your concerns with comments in rc.* files being outdated, a short
advice can be put
at the beginning of each file warning users to take comments in the file as
a very general
reference, guiding them to the man page for newer help, descriptions and
instructions.