edited setup docs for CodeHilite with Pygments

[krother]

Improved the setup documentation when rendering Python code with Pygments and CodeHilite. Added a link to the Pygments CSS files and emphasized that not installing pygments does not cause an error message.

[mitya57]

I don't like the idea of linking to third-party CSS. Instead, one can get the CSS using Pygments API:

from pygments.formatters import HtmlFormatter
HtmlFormatter().get_style_defs('.codehilite')

[krother]

I agree - that would introduce another dependency. I would find it useful though to include the above sniplet in the documentation for the extension.

[waylan]

I have been aware of and intending to link to the third party CSS for some time now. Those CSS files have been generated from calling the Pygments API. But I think @mitya57's concern is valid. I would prefer to leave the note in place and link to the CSS files from there. As a note, it is more like an "aside" and not part of the main body. Or maybe it should be in a "see also" style note.

In any event, the current documentation is lacking. Back when I first drafted it, Pygments documentation was different than it is today and we linked to instructions on how to generate the CSS from Pygment's API. Today, I don't even know where Pygments documents that. Even if we find it, what's to stop them from moving it again. We should just document it ourselves.

Thanks for kickstarting this @krother.

[krother]

Let me know how I can help with this. I am using Python and Markdown daily for writing things. Your library is a key component that glues my blog server together.

[waylan]

I made some additional changes in f3f7687. That should address any concerns raised here. Thanks again.