Remix ParentNode

[Elchi3]

(Oh wow, what a mess.)

This PR takes apart the compat table at https://developer.mozilla.org/en-US/docs/Web/API/ParentNode#browser_compatibility and restructures things according to the new mixin data guideline.

Fun fact: In the past some folks suggested that documenting mixins instead of real APIs will lead to a lot of pages and that's why mixin pages are preferable. Well, all the pages happened anyway already!? All of the following pages exist in addition to the mixin page and so we had multiple data points (which this PR removes). Sigh.

https://developer.mozilla.org/en-US/docs/Web/API/Document/querySelector
https://developer.mozilla.org/en-US/docs/Web/API/DocumentFragment/querySelector
https://developer.mozilla.org/en-US/docs/Web/API/Element/querySelector
https://developer.mozilla.org/en-US/docs/Web/API/Document/querySelectorAll
https://developer.mozilla.org/en-US/docs/Web/API/DocumentFragment/querySelectorAll
https://developer.mozilla.org/en-US/docs/Web/API/Element/querySelectorAll

[foolip]

I can check this against the collector too, but don't block on that if you want to merge.

[foolip]

I've applied suggestions for everything the collector produced diffs for and then some. Hope it's clear what's from the collector and what's a safe guess, I've commented at least once for each but not attributed every single change to a source.

Since I've done this manually in the review UI, errors are still possible, please check for reasonableness.

[Elchi3]

Thanks, very useful to have this all in now! Firefox Android 78 doesn't exist, so it is bumped to 79. Otherwise it all made sense to me.

[foolip]

Argh, I discovered a lot more on a second look.

[Elchi3]

Thanks for the detailed second look!