Ecma262: Use cross-references for things like `[[Set]]` and `?`

[Manishearth]

It's surprising to me that these operations are not linkable. Especially ?, which is a not-immediately-obvious shorthand that's used throughout the spec.

[ljharb]

The ? and ! prefixes, at least, are a learn-once thing; being able to quickly get from an invocation of an internet method to all the internal methods defined with that name in the spec, however, would save a ton of ongoing time and frustration.

[bakkot]

For [[Set]] and friends, see https://github.com/tc39/ecmarkup/issues/116, though in the mean time we could just add dfns to the definitions. (Though that would make them italic, which is maybe undesirable.)

[ExE-Boss]

Well, the thing with ? and ! is that they’d have to be scoped to <emu‑alg>, otherwise it could cause arbitrary ? and ! in the document to auto‑link, which we definitely don’t want.

[ljharb]

@ExE-Boss I'd expect it to only autolink ? or ! when followed by a space, and an abstract operation name, which should hopefully cover those edge cases.

[gsnedders]

The ? and ! prefixes, at least, are a learn-once thing

As someone who looks at the spec only occasionally, I can guarantee they aren't a learn-once thing. And even if they are a learn-once thing, finding their definitions isn't easy, which presents a barrier to learning what they do mean.