use trigger_event instead of dispatch

Author: iMattPro

controller/admin_controller.php

@@ -336,7 +336,7 @@ protected function add_edit_page_data($entity)
 		* @event phpbb.pages.acp_add_edit_page
 		* @since 1.0.0-RC1
 		*/
-		$this->dispatcher->dispatch('phpbb.pages.acp_add_edit_page');
+		$this->dispatcher->trigger_event('phpbb.pages.acp_add_edit_page');
 
 		// Set template vars for Page Template select menu
 		$this->create_page_template_options($entity->get_template());