code: protected function lint(OutputInterface $output, Ciconia $ciconia, $content)
      {
          try {
              $ciconia->render($content, array('strict' => true));
              $output->writeln('No syntax errors detected.');
  
              return 0;
          } catch (SyntaxError $e) {
              $output->writeln('<error>' . $e->getMessage() . '</error>');
  
              return 1;
          }
      }
docs: Lints the content
  
  @param OutputInterface $output  The OutputInterface instance
  @param Ciconia         $ciconia The Ciconia instance
  @param string          $content The markdown content
  
  @return int