Support for syntax highlighting

[ad-si]

It would be cool if there was a config flag to switch on syntax highlighting

[martijnbastiaan]

I'd like to keep this package focused on its core: providing a "pretty" replacement for Aeson's default printer. I feel packages like Pygments (+hpygments) will do a much better job than we could reasonably do. Sorry @ad-si!

[ad-si]

I think a JSON syntax highlighter is so simple (specifying one color for the key and another one for the value - e.g. this file) that it would not unreasonable extend the scope of the package, but that's of course your call. At any rate, thanks for your work on this package!

[martijnbastiaan]

Hmm, I had overlooked that there's already a PR open and that the original maintainer/author was in favor of it. In that case, I'd like to honor it. Maybe we can get the PR in a mergeable state.