[Groff] -s flag

[Daniel Senderowicz]

Werner,

I picked groff-current and noticed that you documented in the
man page of grn the -s flag. I purposedly left it out because
groff doesn't provide both options \D'P...' and \D'p...' that
are outlined and not-outlined shaded polygons. Therefore, I
switched the -s option making the "traverse twice" the default,
so if the gremlin file contains an outlined polygon it will
properly do it.  If you place the -s flag in the command line,
the interior won't be painted, that is not what you want in most
cases. If you still want to document the flag, you can say that
can be used to eliminate shading.

Dan