docsify uses Prism to highlight code blocks in your pages. By default it only supports CSS, JavaScript and HTML. You can make Prism load additional languages:
<script src="//cdn.jsdelivr.net/npm/docsify/lib/docsify.min.js"></script>
<script src="//cdn.jsdelivr.net/npm/prismjs/components/prism-bash.min.js"></script>
<script src="//cdn.jsdelivr.net/npm/prismjs/components/prism-php.min.js"></script>
?> Check the component files list for more options.