Add Performance APIs

[Elchi3]

Web features for the Performance APIs, see https://developer.mozilla.org/en-US/docs/Web/API/Performance_API

Adds a new "Performance" group consisting of these features:

• Performance (main feature, uses compute_from)
• Back/forward cache blocking reasons
• Element timing
• Event timing
• Largest contentful paint (LCP)
• Layout instability
• Long tasks
• Memory measurement
• Navigation timing
• Page visibility state
• Paint timing
• Resource timing (initial support)
• Resource size
• Server timing

[autonome]

First pass review, but it's a big PR, so should get another review as well.

• 👍🏼 on the group rename
• 👍🏼 on removing performance from the feature names
• 👍🏼 on overall feature breakdown/composition
• The descriptions seemed generally fine but IIRC we've tended away from using interface and instead making active descriptions of the implementation, should get a 2nd opinion here

[ddbeck]

A bunch of ideas for you!

[ddbeck]

There should probably be something like html.global_attributes.elementtiming in here, right?

[Elchi3]

hm, there isn't such a key in BCD. The docs have no compat table either. https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/elementtiming. Not sure if it is "global" either:

This attribute may be applied to <img>, <image> elements inside an <svg>, poster images of <video> elements, elements which have a background-image, and elements containing text nodes, such as a <p>.

[ddbeck]

It turns out there's no actual specification for this (though its reflection is via Element). I filed mdn/browser-compat-data#24788

[ddbeck]

This is ready, apart from some messes I made.

I caused the conflicts by merging a change to the specs drafts script. Merging main, running update-drafts on the affected specs, and refreshing the dist should fix it up nicely.

I also suggested some fixes to typos that I introduced.

[Elchi3]

Thanks Daniel, I think I also caused a bit of a mess by manually updating drafts plus the latest BCD release actually contained new Performance API keys plus the new draft collection now also contains sub features without a spec_url.

In theory it should be all fixed now and we can be sure that all keys have been mapped!

[ddbeck]

It turns out there's no actual specification for this (though its reflection is via Element). I filed mdn/browser-compat-data#24788