Add support for tmLanguage json schema

[jonaprieto]

I think it should be easy since it looks similar to the Atom spec. See here: https://raw.githubusercontent.com/martinring/tmlanguage/master/tmlanguage.json

This variant is more readable and better for maintenance.

[jonaprieto]

This format can be used for vscode output instead of the current flag, which btw, it should be renamed.