Support JSON, CSON, and XML/Plist grammar formats

[Alhadis]

These formats are used by Atom, VS Code and TextMate, and many high-quality grammars are written in these flavours (though I recall reading that Sublime supports these formats too).

Rationale: I've written hundreds of TextMate-compatible grammars, but they're all in CSON format. Most of them were written for use on GitHub. I'd kill to see my highlighting work faithfully reproduced by my terminal.

[mmdbalkhi]

Hi @Alhadis, I checked now and they are supported (syntax-highlighting) of course if you mean grammar format.

• bat version: 0.22.0(1f9519d8)

[keith-hall]

The upstream issue for this feature request is https://github.com/trishume/syntect/issues/418