Update service_container/service_subscribers_locators.rst

Co-Authored-By: XuruDragon <xurudragon@gmail.com>

Author: OskarStark

service_container/service_subscribers_locators.rst

@@ -455,7 +455,7 @@ retrieve the ``handler_two`` handler :
 
     class HandlerCollection
     {
-        public function __construct(ServiceLocator $serviceLocator)
+        public function __construct(ServiceLocator $locator)
         {
             $handlerTwo = $locator->get('handler_two'):
         }