Bug#711165: xbacklight: mention at least 1 step

[jidanni@jidanni.org]

Package: xbacklight
Version: 1.1.2-1
Severity: wishlist
File: /usr/share/man/man1/xbacklight.1.gz

At
       -steps number
              Number of steps to take while fading. Default is 20.
Could add
       (Needs at least 1.)