Move javascript.statements.default.exports to exports.default; remove default.switch

[queengooborg]

This PR fixes #4898. During the KR to achieve 100% real values for JavaScript, I had gotten a little bit confused in regards to the structure of the default keyword. The keyword doesn't have its own compatibility data, and does not have any function on its own; only when used within the switch and export keywords. Furthermore, depending on which keyword its used for, it has a different meaning.

This PR refactors the default keyword to be two subfeatures under switch and export instead of a single feature with two subfeatures.

Edit: as per request, default.switch was later removed, leaving only default.export.

[Elchi3]

Thanks for looking into this!

I agree this is confusing and I think the page https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/default makes no sense and should be redirected to the switch statement.

Also, javascript.statements.switch.default should be removed entirely. The default switch keyword is naturally part of https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/switch and doesn't need special compat data.

For default exports, it makes sense to have the compat data under javascript.statements.export.default as you've done here. So, that's good. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/export already talks about default exports, we don't need https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/default for that.

So, tl;dr; please don't add javascript.statements.switch.default and then this should be good to go.

[Elchi3]

Thank you! 👍