manpage: add -geometry

nx-X11/programs/Xserver/hw/nxagent/man/nxagent.1

@@ -262,6 +262,25 @@ must be supported by the real server.  Use
 to obtain a list of supported visual depths on the real server before
 starting \fBnxagent\fR.
 .TP 8
+.B \-geometry \fIW\fBx\fIH\fB+\fIX\fB+\fIY\fP
+This option specifies the geometry parameters for the top-level
+\fBnxagent\fR window.  See \(lqGEOMETRY SPECIFICATIONS\(rq in
+.BR X (__miscmansuffix__)
+for a discusson of this option's syntax.  This window corresponds to
+the root window of the nested server.  The width
+.I W
+and height
+.I H
+specified with this option will be the maximum width and height of
+each top-level \fBnxagent\fR window.  \fBnxagent\fR will allow the
+user to make any top-level window smaller, but it will not actually
+change the size of the nested server root window.  If this option is
+not specified, \fBnxagent\fR will choose
+.I W
+and
+.I H
+to be 3/4ths the dimensions of the root window of the real server.
+.TP 8
 .B \-dpi \fIresolution\fP
 sets the resolution for all screens, in dots per inch.
 To be used when the server cannot determine the screen size(s) from the