Option to disable highlighting

[wdanilo]

Hello! I would love to be able to disable highlighting on some systems (for example in terminals which does not support it). It would be great if we could just apply a "style" to our parser. Such style could contain color definitions and information if we want the colors or not.

[quchen]

You can use the plain function to remove highlighting from a Doc for the time being. It would be nice to have the highlighter more customizable though, yes.