Highlight links (and mark them usable too)

[kizu]

There can be a lot of links in code — to stylesheets, scripts, images etc. — it would be nice to have them highlighted and be actual links, so you could jump to the associated resources.

However, there can be an issue with relative links — in most cases it wouldn't be obvious to the script what is the base for them. So as a starter, only the absolute links can be the actual links and then there can be an option to set the base url manually (in the pre/code attributes maybe?) and if so, then use it with concatenation with the relative links inside.

[LeaVerou]

Good idea.

[LeaVerou]

Done. :) Check this commit: 483831e