docs: create dedicated documentation for JSON

[lumirlumir]

Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request?

In this PR, I've created dedicated documentation for JSON.

It was briefly discussed in #104 (comment).

I've also updated rule's URL and ESLint config file accordingly.

What changes did you make? (Give an overview)

I've created dedicated documentation for JSON.

Related Issues

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

I'll take a look at the rule section automation in README.md once this PR is accepted.

• https://github.com/eslint/css/blob/main/tools/update-rules-docs.js
• https://github.com/eslint/markdown/blob/main/tools/update-rules-docs.js

[nzakas]

Thanks for getting started on this. I left some suggestions to clarify things and to ensure consistent formatting across plugin rule docs.

[lumirlumir]

@nzakas Thanks for your suggestions. I’ve addressed all the reviews.

[nzakas]

LGTM. Thanks.