update documentation of what's in the DISC field output by pstat -t

usr.sbin/pstat/pstat.8

@@ -1,4 +1,4 @@
-.\"	$NetBSD: pstat.8,v 1.9 1996/05/02 00:13:08 cgd Exp $
+.\"	$NetBSD: pstat.8,v 1.10 1996/05/31 00:27:19 cgd Exp $
 .\"
 .\" Copyright (c) 1980, 1991, 1993, 1994
 .\"	The Regents of the University of California.  All rights reserved.
@@ -165,18 +165,23 @@ hangup on close
 .It PGRP
 Process group for which this is controlling terminal.
 .It DISC
-Line discipline; blank is old tty
-OTTYDISC
-or
-.Ql new tty
+Line discipline;
+.Ql term
 for
-NTTYDISC
-or
-.Ql net
-for
-NETLDISC
-(see
-.Xr bk 4 ) .
+TTYDISC (see
+.Xr termios 4 ) ,
+.Ql tab
+for TABLDISC (see
+.Xr tb 4 ) ,
+.Ql slip
+for SLIPDISC (see
+.Xr sl 4 ) ,
+.Ql tab
+for PPPDISC (see
+.Xr ppp 4 ) ,
+.Ql tab
+for STRIPDISC (see
+.Xr strip 4 ) .
 .El
 .It Fl v
 Print the active vnodes.  Each group of vnodes corresponding