Suggest documentation of "soft limit" logic for chpst

[Jared Rhine <jared@wordzoo.com>]

It might be helpful to have a little bit of discussion on the chpst
manpage which outlines that chpst is dealing with soft limits.

I had been trying to raise the limit on number of open files via 'chpst
-o 10000'.  I thought this was working properly, so I was focused on
examining the daemon for bugs.  Then I finally had the insight to test
whether 'chpst -o 10000 && ulimit -a' was doing what I expect.  Now I'm
doing a 'ulimit -n 10000' instead of a 'chpst -o 10000'.

I had read the manpage a couple of times while doing this investigation,
but it's brief with respect to what chpst is really doing with these
switches.  It wasn't until I saw "softlimit(8)" at the bottom that I
started to suspect the source of my problem.  Maybe mentioning the
actual logic in-line with the manpage text would be useful.

I'd also be in favor of chpst being able to raise limits (hard ulimit)
to emulate ulimit more directly, but that's a separate conversation.