(a) Note that the default securelevel value is -1, in -current and -stable.
(b) Mention kernel sysctl variable that controls securelevel.
(c) Add warning the `fsck' will fail if securelevel >= 2.
(d) Suggest end of /etc/rc as the right place to raise securelevel.
and one spelling fix.
PR: 2850
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
man pages up to mdoc guidelines and fix some minor formatting glitches.
Also fixed a number of man pages to not abuse the .Xr macro to
display functions and path names and a lot of other junk.
