[Feature Request] Implement :has selector

[AlJohri]

It would be great to implement the :has css selector, now supported by most major browsers other than Firefox.

• Spec: https://www.w3.org/TR/selectors-4/#has-pseudo
• Browser Support: https://caniuse.com/css-has
• Firefox Ticket: https://bugzilla.mozilla.org/show_bug.cgi?id=418039

[jasonm23]

Firefox even supports :has, just needs to be enabled in config. A thumbs up to add this feature too.