fix: You can't insert before the first element with method insertBefore

Author: stanislavkrsv

DS/LinkedList/Classes/LinkedList.php

@@ -74,7 +74,6 @@ public function insertBefore(string $data = NULL, string $query = NULL) {
                     } else {
                         $previous->next = $newNode;
                     }
-                    $previous->next = $newNode;
                     $this->_totalNode++;
                     break;
                 }