Added dark version of the code-prettify.js template

I added the dark version of the template that would be used for the code-prettify.js highlighting script. I thought I'd clarify that I'm not sure it's 100% as it should be, if you could check and make sure that everything is correct, that would be nice.

Could you please make sure that the colors are correct? I will start working on the light version soon.

I also fixed the Vim spell checking highlighting, you can of course fix that before merging. :)