remove some incorrect bash symbols

Signed-off-by: lixiaobing10051267 <li.xiaobing1@zte.com.cn>

docs/userguide/networking/get-started-overlay.md

@@ -47,7 +47,7 @@ $ docker network create \
 
 # Create an nginx service and extend the my-multi-host-network to nodes where
 # the service's tasks run.
-$ $ docker service create --replicas 2 --network my-multi-host-network --name my-web nginx
+$ docker service create --replicas 2 --network my-multi-host-network --name my-web nginx
 
 716thylsndqma81j6kkkb5aus
 ```

docs/userguide/networking/index.md

@@ -428,7 +428,7 @@ $ docker network create \
 
 # Create an nginx service and extend the my-multi-host-network to nodes where
 # the service's tasks run.
-$ $ docker service create --replicas 2 --network my-multi-host-network --name my-web nginx
+$ docker service create --replicas 2 --network my-multi-host-network --name my-web nginx
 
 716thylsndqma81j6kkkb5aus
 ```