Add command option parameter in console-url.rst

There are  options (--rdp,--serial,--mks) in console-url.rst,
but it has no these options after "os console url show", therefore,
I add them.

Change-Id: I4fd6b14f37cb5751021b8d33d4a65dae17e4e4e5

Author: zheng yin

doc/source/command-objects/console-url.rst

@@ -16,6 +16,7 @@ Show server's remote console URL
 
     os console url show
         [--novnc | --xvpvnc | --spice]
+        [--rdp | --serial | --mks]
         <server>
 
 .. option:: --novnc