docs: pass on sub-command help

cli/app/undeploy.go

@@ -78,8 +78,7 @@ This does not destroy any of the application data.
 However, you should remain vigilant, as your swarm installation will consider
 any previously attached volumes as eligible for pruning once undeployed.
 
-Passing "-p/--prune" does not remove those volumes.
-`,
+Passing "-p/--prune" does not remove those volumes.`,
 	Action: func(c *cli.Context) error {
 		app := internal.ValidateApp(c)
 		stackName := app.StackName()