Add document, document fragment, document type

[autonome]

kitchen sink at this point, pulled from various drafts.

Ok, whittling down to keys which match the following criteria:

• superkeys like api.Document
• keys which refer directly to the document itself or change it, eg document.lastModified and `document.
• document-level collections, eg document.images and document.forms (yes, there may be "primary" features for the thing being collected but the document shortcut is document-level)

Need to determine whether to put other interface impls in the feature or in the interface - eg, document.append is impl of Element... so do we add all the append keys to their feature or add them all to an Element feature? TBD will ask in chat/meeting.

Will see what's left after that culling and classify the remainders.

[autonome]

Ready for a first pass. There's not any real standalone feature candidates in the key list for Document. There's a couple notes on Caniuse keys that are related.

Open question is what approach for keys like createTreeWalker - there'll be a TreeWalker feature coming out of the DOM PR I've got going. Things like Ranges also will be feature. I assumed it'd go with the specific feature vs leaving it here, but worth asking if there's different opinion there.

Aside from one-off keys that'll get poached into future features, some things that might make standalone features:

• head as noted in the PR
• designMode
• referrer
• dir (add to other intl features/group?)
• maybe there's a better home for the visibility keys?

Aha, so there's this: https://caniuse.com/dom-manip-convenience

The description shows its age enough that I'm skeptical we want to align around that bag of APIs specifically.

However, there may be something to a "working w/ the DOM and nodes" collection of features, looking through developer lens.

[ddbeck]

I think a lot of this stuff is going to get swept into a monolithic DOM feature. I'd appreciate if other reviewers also had a look through https://github.com/web-platform-dx/web-features/pull/2007/files#r1813040012.

[autonome]

Closing to fold into #2007