be more descriptive in the description of what rev(1) does

usr.bin/rev/rev.1

@@ -1,4 +1,4 @@
-.\"	$NetBSD: rev.1,v 1.4 1997/10/19 14:03:29 lukem Exp $
+.\"	$NetBSD: rev.1,v 1.5 2001/01/21 01:01:08 lukem Exp $
 .\"
 .\" Copyright (c) 1985, 1992, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -33,12 +33,12 @@
 .\"
 .\"	@(#)rev.1	8.1 (Berkeley) 6/9/93
 .\"
-.Dd June 9, 1993
+.Dd January 21, 2001
 .Dt REV 1
 .Os
 .Sh NAME
 .Nm rev
-.Nd reverse lines of a file
+.Nd reverse order of characters of lines in a file
 .Sh SYNOPSIS
 .Nm
 .Op Ar file