qapi: fix example of query-memdev command

Example output is missing mandatory argument @share for the return
JSON object. Add it.

Signed-off-by: Victor Toso <victortoso@redhat.com>
Message-Id: <20220331190633.121077-10-victortoso@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

qapi/machine.json

@@ -839,6 +839,7 @@
 #          "merge": false,
 #          "dump": true,
 #          "prealloc": false,
+#          "share": false,
 #          "host-nodes": [0, 1],
 #          "policy": "bind"
 #        },
@@ -847,6 +848,7 @@
 #          "merge": false,
 #          "dump": true,
 #          "prealloc": true,
+#          "share": false,
 #          "host-nodes": [2, 3],
 #          "policy": "preferred"
 #        }