Small code fixes in API code

pub/api/classes/API_usergroups.php

@@ -3,6 +3,7 @@
 namespace api\classes;
 
 use api\classes\API;
+use JetBrains\PhpStorm\NoReturn;
 
 require_once 'API.php';
 
@@ -17,6 +18,7 @@ class API_usergroups extends API
         return $items;
     }
 
+    #[NoReturn]
     public function createUsergroups()
     {
         # check if the user_group already exists
@@ -70,6 +72,7 @@ class API_usergroups extends API
         }
     }
 
+    #[NoReturn]
     public function deleteUsergroup()
     {
         # check if the user group exists
@@ -113,6 +116,7 @@ class API_usergroups extends API
         return $weight;
     }
 
+    #[NoReturn]
     public function updateUserGroup()
     {
         # check if the user group exists