code: protected function registerMarkdownEnvironment()
      {
          $app = $this->app;
  
          $app->singleton('commonmark.environment', function ($app) {
              $config = $app['config']['markdown'];
              $environment = Environment::createCommonMarkEnvironment();
  
              if ($config['configurations']) {
                  $environment->mergeConfig($config['configurations']);
              }
  
              foreach ($config['extensions'] as $extension) {
                  if (class_exists($extension)) {
                      $environment->addExtension(new $extension());
                  }
              }
  
              return $environment;
          });
  
          $app->alias('commonmark.environment', Environment::class);
      }
docs: Register the CommonMark Environment.
  
  @return void