reduce more .Nd to one line and kill more .Tn

src/lib/libutil/login_fbtab.3

@@ -1,4 +1,4 @@
-.\"	$OpenBSD: login_fbtab.3,v 1.12 2014/09/08 01:27:54 schwarze Exp $
+.\"	$OpenBSD: login_fbtab.3,v 1.13 2015/09/10 15:53:26 schwarze Exp $
 .\"
 .\" Copyright 1995 by Wietse Venema.  All rights reserved.  Some individual
 .\" files may be covered by other copyrights.
@@ -15,13 +15,12 @@
 .\" warranties, including, without limitation, the implied warranties of
 .\" merchantibility and fitness for any particular purpose.
 .\"
-.Dd $Mdocdate: September 8 2014 $
+.Dd $Mdocdate: September 10 2015 $
 .Dt LOGIN_FBTAB 3
 .Os
 .Sh NAME
 .Nm login_fbtab
-.Nd implement device security based on
-.Pa /etc/fbtab
+.Nd implement device security based on fbtab(5)
 .Sh SYNOPSIS
 .In sys/types.h
 .In util.h