Mark syntax highlighting task as completed in TODO.md

Author: jedisct1

www/TODO.md

@@ -21,7 +21,7 @@ This document outlines planned improvements and future tasks for the IPCrypt web
 
 ### Technical Implementation
 
-- [ ] Add syntax highlighting for code examples
+- [x] Add syntax highlighting for code examples
 - [x] Implement proper meta tags for better SEO
 - [x] Create a sitemap.xml file
 - [x] Add schema.org markup for better search results