swarm leave is not only for workers

the "docker swarm leave" command description
mentioned that the command can only be used
for workers, however, the command can also
be used for managers (using the `-f` / `--force`
option).

this patch removes the "(workers only)" part
of the command description.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit f89eee5d9d3c01bc6d498fcb1163ec199e6c3078)
Signed-off-by: Victor Vieux <vieux@docker.com>

cli/command/swarm/leave.go

@@ -19,7 +19,7 @@ func newLeaveCommand(dockerCli *command.DockerCli) *cobra.Command {
 
 	cmd := &cobra.Command{
 		Use:   "leave [OPTIONS]",
-		Short: "Leave the swarm (workers only)",
+		Short: "Leave the swarm",
 		Args:  cli.NoArgs,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return runLeave(dockerCli, opts)

docs/reference/commandline/swarm_leave.md

@@ -18,7 +18,7 @@ keywords: "swarm, leave"
 ```markdown
 Usage:	docker swarm leave [OPTIONS]
 
-Leave the swarm (workers only)
+Leave the swarm
 
 Options:
   -f, --force   Force this node to leave the swarm, ignoring warnings