feat: Export internal constructs for other plugin authors

[Sidnioulz]

Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request?

Exports internal JSONLanguage and JSONSourceCode classes to allow further specialisation, so that plugins for JSON-based domain-specific languages can reuse that code without copying it.

What changes did you make? (Give an overview)

• Added named exports to the project index for JSONLanguage and JSONSourceCode

Related Issues

This was requested to the JSON plugin maintainer on Discord. Happy to open an issue for traceability if desired.

Is there anything you'd like reviewers to focus on?

• Is feat okay as a commit type to use? Or do refactor or chore trigger patch releases?

[nzakas]

LGTM. Since we've still in v0.x, feat is appropriate.

[nzakas]

Looks like there's a validation error. Can you run npm run fmt and re-push?

[Sidnioulz]

Looks like there's a validation error. Can you run npm run fmt and re-push?

Oops! I'm too used to having this on file save in my IDE for my own projects, forgot to check for it :)

[ipanasenko]

I think this is exactly what was missing for me, when I tried to write my own json plugin, thanks! ❤️