[Feature request] language guess for code blocks #361

I've bee looking for a bit but I can't find a way to add language detection to code blocks. Am I missing something or is this feature not implemented yet?

For now it gives something similar to what we have on github:

def f(x):
    return x

def f(x):
    return x

I would like to have something like in stackoverflow:

If this doesn't exist, do you have an idea on what can be done? Thanks.