New tutorial for Drupal (#1859)

This adds a new tutorial.

index.html

@@ -241,6 +241,7 @@ <h1>Third-party tutorials</h1>
 		<li><a href="https://usetypo3.com/fs-code-snippet.html">A code snippet content element powered by Prism.js for TYPO3 CMS</a></li>
 		<li><a href="https://auralinna.blog/post/2017/code-syntax-highlighting-with-angular-and-prismjs">Code syntax highlighting with Angular and Prism.js</a></li>
 		<li><a href="https://mkaz.blog/wordpress/code-syntax-highlighting-in-gutenberg/">Code syntax highlighting in Gutenberg, WordPress block editor</a></li>
+		<li><a href="https://karlkaufmann.com/writing/technotes/code-highlighting-prism-drupal">Code Highlighting with Prism.js in Drupal</a></li>
 	</ul>
 
 	<p>Please note that the tutorials listed here are not verified to contain correct information. Read at your risk and always check the official documentation here if something doesn’t work :)</p>