Add a SEE ALSO section to znc(1) man page.

Thanks for ryan-c for the hint.

man/znc.1

@@ -146,3 +146,8 @@ for remembering module settings that are not part of
 .TP
 .IB ~/.znc/moddata/ MODULENAME /
 This is where global modules may save their settings.
+.SH SEE ALSO
+.BR znc-buildmod (1)
+.PP
+Full documentation at:
+.I https://znc.in/