If I understand it correctly, SO is supporting Google Prettify. There is no information about this within the Markdown editing notes (the Code section of the toolbar and in the advanced help).
I think it would be a good idea to add this information, as the link to the Prettify docs doesn't exactly give the details I'd like. For example, an explicit example of how to specify a language (for example, it is unclear if the Prettify comment must be indented or not) and what languages/tags are supported.