docs: pass on sub-command help

cli/app/rollback.go

@@ -34,14 +34,13 @@ var appRollbackCommand = cli.Command{
 	},
 	Before: internal.SubCommandBefore,
 	Description: `
-This command rolls an app back to a previous version if one exists.
+This command rolls an app back to a previous version.
 
 You may pass "--force/-f" to downgrade to the same version again. This can be
 useful if the container runtime has gotten into a weird state.
 
 This action could be destructive, please ensure you have a copy of your app
-data beforehand.
-`,
+data beforehand.`,
 	BashComplete: autocomplete.AppNameComplete,
 	Action: func(c *cli.Context) error {
 		app := internal.ValidateApp(c)