use prismejs for syntax highlight

Author: KHOUBZA Younes

_includes/head.html

@@ -51,3 +51,7 @@
         gtag('config', 'G-T4D78SM7TC');
     </script>
 {% endunless %}
+
+<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/prismjs@1.28.0/themes/prism.min.css">
+<script defer src="https://cdn.jsdelivr.net/npm/prismjs@1.28.0/prism.min.js"></script>
+<script defer src="https://cdn.jsdelivr.net/npm/prismjs@1.28.0/plugins/autoloader/prism-autoloader.min.js"></script>