fix the wrong info while specifying the command with the "--help"

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

docs/tutorials/usingdocker.md

@@ -73,9 +73,11 @@ To see usage for a specific command, specify the command with the `--help` flag:
 
     Attach to a running container
 
-      --help              Print usage
-      --no-stdin          Do not attach stdin
-      --sig-proxy=true    Proxy all received signals to the process
+    Options:
+      --detach-keys string   Override the key sequence for detaching a container
+      --help                 Print usage
+      --no-stdin             Do not attach STDIN
+      --sig-proxy            Proxy all received signals to the process (default true)
 
 > **Note:**
 > For further details and examples of each command, see the