Add type of group in nxos_linkagg module doc (#54769)

Signed-off-by: Trishna Guha <trishnaguha17@gmail.com>
(cherry picked from commit 6155701e36)

lib/ansible/modules/network/nxos/nxos_linkagg.py

@@ -36,6 +36,7 @@ options:
       - Channel-group number for the port-channel
         Link aggregation group.
     required: true
+    type: str
   mode:
     description:
       - Mode for the link aggregation group.