Escape the backslash character.

git-svn-id: https://hamlib.svn.sourceforge.net/svnroot/hamlib/trunk@2268 7ae35d74-ebe9-4afe-98af-79ac388436b8

tests/rigctl.1

@@ -303,7 +303,7 @@ power in milli-Watts.  The \fIfrequency\fP and \fImode\fP also need to be
 provided as output power may vary according to these values.
 .TP
 .B w, send_cmd
-Send raw command string to rig. Binary protocols enter values as \0xAA\0xBB
+Send raw command string to rig. Binary protocols enter values as \\0xAA\\0xBB
 .SH EXAMPLES
 Start \fBrigctl\fP for a Yaesu FT-920 using a USB to serial adapter in 
 interactive mode: