Highlighting should be language specific

[chasenlehara]

Right now, the styles in prettify.less are applied to all languages; no language-specific highlighting occurs.

This causes some weird highlighting in some cases. For example, in Weather Report Guide (Simple), everything after the // is commented out for text that is in a ``` block:

This would be easy to work around if you could add text as the highlighting, but the .com style still gets applied, so that workaround doesn’t work.

[chasenlehara]

I think this is fixed with #15 #17