Align arg with other cli

Signed-off-by: yupeng <yu.peng36@zte.com.cn>

cmd/docker/docker.go

@@ -22,7 +22,7 @@ func newDockerCommand(dockerCli *command.DockerCli) *cobra.Command {
 	var flags *pflag.FlagSet
 
 	cmd := &cobra.Command{
-		Use:              "docker [OPTIONS] COMMAND [arg...]",
+		Use:              "docker [OPTIONS] COMMAND [ARG...]",
 		Short:            "A self-sufficient runtime for containers",
 		SilenceUsage:     true,
 		SilenceErrors:    true,

docs/reference/commandline/cli.md

@@ -20,7 +20,7 @@ or execute `docker help`:
 
 ```bash
 $ docker
-Usage: docker [OPTIONS] COMMAND [arg...]
+Usage: docker [OPTIONS] COMMAND [ARG...]
        docker [ --help | -v | --version ]
 
 A self-sufficient runtime for containers.

man/docker.1.md

@@ -5,7 +5,7 @@
 docker \- Docker image and container command line interface
 
 # SYNOPSIS
-**docker** [OPTIONS] COMMAND [arg...]
+**docker** [OPTIONS] COMMAND [ARG...]
 
 **docker** daemon [--help|...]