[feature/module_services] Minor changes to docblocks and migration file

controller/main.php

@@ -115,7 +115,7 @@ class main
 	*
 	* @param \phpbb\di\service_collection $modules Board3 Modules service
 	*						collection
-	* @return void
+	* @return null
 	*/
 	protected function register_modules($modules)
 	{

migrations/v210_beta1.php

@@ -358,7 +358,7 @@ class v210_beta1 extends \phpbb\db\migration\migration
 				'module_status'		=> 1,
 			),
 			array(
-				'module_classname'		=> 'attachments',
+				'module_classname'		=> '\board3\portal\modules\attachments',
 				'module_column'		=> 1,
 				'module_order'		=> 6,
 				'module_name'		=> 'PORTAL_ATTACHMENTS',