I've been writing quite a lot of documentation lately, and my previous decision to require an HTML comment in order to get syntax highlighting of Ceylon code started to look like the wrong choice. Since the vast majority of the code blocks on the site are going to be Ceylon source, and since we're (almost?) always going to want that highlighted I've changed the rules:

• Now all indented code blocks will be assumed to be Ceylon source code that requires syntax highlighting, unless indicated otherwise.
• If the source code is not Ceylon, you can use a <!-- lang: foo --> comment (having setup the syntax highlighter and gsub transformer to do highlighting for the language foo).
• If you don't want any highlighting at all use <!-- lang: none -->