This fixes the type definitions for CJS by leveraging a namespace. ESM type definitions were added, which export all types from the CJS types, and exports the exported stylelint object as default.

Some tweaks were made to the package.json exports, to resolve the types correctly for both CJS and ESM.

The type test was modified to fix CJS usage. Also a test was added for ESM usage. Stylelint was using tsconfig paths, which is a commonly misunderstood / misused feature that should rarely be used. This was removed, so TypeScript resolves the types based on package exports.

Which issue, if any, is this issue related to?

Refs 7309

Is there anything in the PR that needs further explanation?

https://arethetypeswrong.github.io/?p=stylelint@16.0.0 before this PR:

After uploading the result of npm pack after this PR:

This is best reviewed with whitespace changes disabled.