add missing description of "EnableSshKeysign".

crypto/dist/ssh/ssh_config.5

@@ -1,4 +1,4 @@
-.\"	$NetBSD: ssh_config.5,v 1.6 2003/07/24 15:31:55 itojun Exp $
+.\"	$NetBSD: ssh_config.5,v 1.7 2004/03/06 14:33:08 itojun Exp $
 .\"  -*- nroff -*-
 .\"
 .\" Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -240,6 +240,25 @@ will act as a SOCKS4 server.
 Multiple forwardings may be specified, and
 additional forwardings can be given on the command line.
 Only the superuser can forward privileged ports.
+.It Cm EnableSSHKeysign
+Setting this option to
+.Dq yes
+in the global client configuration file
+.Pa /etc/ssh/ssh_config
+enables the use of the helper program
+.Xr ssh-keysign 8
+during
+.Cm HostbasedAuthentication .
+The argument must be
+.Dq yes
+or
+.Dq no .
+The default is
+.Dq no .
+This option should be placed in the non-hostspecific section.
+See
+.Xr ssh-keysign 8
+for more information.
 .It Cm EscapeChar
 Sets the escape character (default:
 .Ql ~ ) .