Leftover `ReturnIfAbrupt` reference

[nicolo-ribaudo]

It's still mentioned in https://tc39.es/ecma262/#sec-implicit-normal-completion:

However, ReturnIfAbrupt has been removed in #3705.

It should just mention "the ? shorthand expansion" (https://tc39.es/ecma262/#sec-shorthands-for-unwrapping-completion-records), and the ? definition should mark the "if x is an abrupt completion, return x" with an explicit Completion() marker, to make it editorially valid.

[bakkot]

Whoops, could have sworn I checked for that.

the ? definition should mark the "if x is an abrupt completion, return x" with an explicit Completion() marker, to make it editorially valid

I don't think this is actually necessary. We have a convention enforced by tooling that we use Completion() to emphasize when we're receiving or returning a completion record, but we don't actually claim anywhere in the document that this is always done, and in this special case I don't think it adds anything since we've just asserted it to be a completion anyway.