For big code blocks it would be nice to have somewhere a badge or any other sign of what the language is in there. While it can be obvious in most cases, for some languages it would be better to show this information.

As a suggestion of the possible design — put the name of the current language in the top right corner as a backgound. However, it would need an extra markup to have it don't scroll with the content of the code block. But if it's acceptable, then it can be done by plain CSS with pseudo-element.