This is now enabled, but there's no default language set, which means [you'll need to provide hinting as to what scheme should be used](https://meta.superuser.com/questions/4266/make-syntax-highlighting-possible-to-enable-with-prettify-language-codes) for it to show. 

On a few tags, by tag kind of makes sense for obvious reasons. However, in others .. it wouldn't, depending on the content of the post. In order to stay consistent, we're just allowing manual hints as needed, which is a little less confusing to the non-ninjas posting their first few contributions.