Support latest Pygments (for improved Haskell syntax, and more)

[declension]

Change Requested

The use of Pygments==2.2.0 (or newer, potentially) to highlight code.

Background

As part of a syntax highlighting problem noted on Haskell-Servant, @teh pushed a PR for Pygments that was merged a while ago.

I've submitted a Pygments dependency bump in the Servant codebase which works locally, but as we use https://readthedocs.org for actually hosting, it won't help solve the real problem unless Pygments is upgraded here too...

[humitos]

Currently, RTD uses pygments==2.0.2. Not sure, but I think that upgrading it to 2.2.0 won't be a big deal. Anyway, in the meanwhile, you could use that particular version in your requirements.txt file for read the docs.

[declension]

@humitos thanks - we have now actually, and it seems to be working well (see latest haskell-servant docs vs previous 0.10 version).

So I guess this is a lower priority for now but still might be nice to have (and FWIW I'll report back if I notice anything weird)