Fatal error: Uncaught Error: Interface 'Stringable' not found in /var/www/html/test-project/my-app/vendor/league/commonmark/src/Output/RenderedContentInterface.php:18 Stack trace: #0 {main} thrown in /var/www/html/test-project/my-app/vendor/league/commonmark/src/Output/RenderedContentInterface.php on line 18