[Groff] removing RUNOFF man page

[Bernd Warken]

Hi folks,

as I will write my own program for RUNOFF, I will remove the man page runoff.man
from the groff source because of name mixing with my future program.  This man
page does not suit to groff anyway.  Sorry for that.

In contrib/RUNOFF/ there is moreover a man page about the file names used by
RUNOFF, roff and groff.  I'll remove the RUNOFF parts and will store it in a
new directory contrib/groff_filenames.

Good luck - bye

Bernd Warken