manpage: remove special casing CONTRIBUTORS

this section was added almost 10 years ago (see commit 60f84190f) back
when sxiv was pretty new and didn't have many contributors.

the situation has obviously changed now, especially with `nsxiv` we have
a fair amount of contributors now. so it makes no sense to special case
a couple of them.

etc/nsxiv.1

@@ -572,12 +572,7 @@ qsmodo
 .EE
 .SH CONTRIBUTORS
 .EX
-Bastien Dejean         <nihilhill at gmail.com>
-Dave Reisner           <d at falconindy.com>
-Fung SzeTat            <sthorde at gmail.com>
-Max Voit               <mvdev at with-eyes.net>
-
-For additional contributors, run `git shortlog -s` in the nsxiv repository.
+For a list of contributors, run `git shortlog -s` in the nsxiv git repository.
 .EE
 .SH HOMEPAGE
 .TP