Add document.write() feature

[captainbrosset]

document.open and document.close are not discouraged in the spec, but they're only useful for document.write anyway, so we might as well group all of these related methods together in a new discouraged feature.

[captainbrosset]

@ddbeck interestingly, adding the two accepts_TrustedHTML keys makes the feature appear as if it's only supported in chromium. Not that it matters since the whole feature is discouraged, and therefore not baseline. But it makes the compat data here a little weird because document.write() has been supported everywhere for a long time.

For consumers who only care about the baseline status, nothing to worry about.
But for those who show the complete compat data, it might make sense to add compute_from: api.Document.write to make the data more like what people would expect. However, doing so here fails the build because that key is deprecated.

[ddbeck]

@captainbrosset you found a bug! I sent #2689 to fix it.

Here's what that fix would look like on this branch: document-write...ddbeck:web-features:fix-document-write

[ddbeck]

Thank you for the review on the other PR, Patrick! I've merged main into this branch and refreshed the dist. All is well now.