Add skipped "launchcheck" command in example

The example command for `wp launchcheck secure` was missing the `launchcheck` part.

php/commands/launchcheck.php

@@ -152,7 +152,7 @@ public function object_cache($args, $assoc_args) {
 	 *
 	 * ## EXAMPLES
 	 *
-	 *   wp secure --skip=wp-content/themes
+	 *   wp launchcheck secure --skip=wp-content/themes
 	 *
 	 */
 	public function secure($args, $assoc_args) {