Allow JSON with comments in jsconfig.json

Created by: mrmckeb

Is your proposal related to a problem?

This is a follow-on from #7248. Right now, we don't support JSONC (JSON with comments) in jsconfig.json files.

Describe the solution you'd like

After a discussion with @iansu, we see two paths:

1. Implement the same solution as we did for TypeScript. This is easy, but would require us making TypeScript a dependency of react-scripts.
2. The above, but instead of installing typescript as a dependency of react-scripts, we would install it to the user's project if they are using a jsconfig.json file and don't have typescript installed.

Discussion is welcome.

If you're interested in picking this up, please let us know.