remove confusing DPMS comment
remove confusing DPMS comment

FRIGN on hackers@suckless.org:
What has been bugging me for quite a while is this DPMS comment that was added
there for no reason. Every sane mind would agree that fiddling with DPMS makes
no sense whatsoever. When I slock, my screen turns off after 10 minutes. So, if
I don't like that, I disable DPMS. If I do, I just fiddle around with my mouse a
bit and get the slock promt.

dtkav/slock