In the application we are going to use TranslatorInterface and call its translate() method passing message key (id), parameters to substitute in the final string, category and target locale.  interface TranslatorInterface {     public function translate(         string $id,         array $parameters = [],         string $category = null,         string $locale = null     ): ?string; }  It is expected that we get final string that we can output to end user from this call:  public function actionT...