qapi: fix example of query-vnc command

The return value is missing the mandatory member @websocket. Fix it.

Signed-off-by: Victor Toso <victortoso@redhat.com>
Message-Id: <20220331190633.121077-6-victortoso@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

qapi/ui.json

@@ -658,6 +658,7 @@
 #                "host":"127.0.0.1",
 #                "service":"50401",
 #                "family":"ipv4"
+#                "websocket":false,
 #             }
 #          ]
 #       }