Fatal error: Uncaught Error: Interface 'League\CommonMark\Extension\ExtensionInterface' not found in D:\xampp\htdocs\vendor\league\commonmark\src\Extension\GithubFlavoredMarkdownExtension.php:21 Stack trace: #0 {main} thrown in D:\xampp\htdocs\vendor\league\commonmark\src\Extension\GithubFlavoredMarkdownExtension.php on line 21