3 more minor bits for fold, banner and ping6

[Brian Poole <raj_(_at_)_cerias_(_dot_)_purdue_(_dot_)_edu>]

Just more little bits I'm stumbling upon as I've been looking 
around the tree. Sorry for putting them all in one email, but
I don't want to annoy everyone by sending each buglet in a 
seperate mail, especially when they are changing like 3 chars ;)

1) usr.bin/fold/fold.1

Synopsis should list file as optional, as fold reads from stdin 
if file is not given as an option.

Line 47:
.Ar file Op Ar ...

should probably read,
.Op Ar file ...


2) usr.bin/banner/banner.c

strncpy -> strlcpy replacement, strlcpy is preferred, correct?

Line 176,7:
                (void)strncpy(word, *argv, sizeof (word) - 1);
                word[sizeof (word) - 1] = '\0';

should probably read,
 		(void)strlcpy(word, *argv, sizeof (word));

3) sbin/ping6/ping6.c

ping6.c reintroduced -m to the usage message rev 1.28, reversing
the backing out of it in rev 1.22 because we don't have it. It
should be backed out again until we have it. As well, the -t
option is not listed in the usage message, but is parsed by
getopt and listed in the man page, so we should probably add it.

Line 2521:
            "usage: ping6 [-dfHmnNqvwW"

should probably read,
            "usage: ping6 [-dfHnNqtvwW"

Enjoy,

-b