Editorial: Update ECMA-402 and -404 references

[gibson042]

trafficstars

Aligns with https://tc39.es/ecma402/#normative-references

Fixes #2808

[michaelficarra]

Discussed this today in the 262 editors' call. We'd prefer to refer specifically to the associated 402 version instead of allowing future versions. This means that

1. For yearly releases, we add a feature to ecmarkup for both 262 and 402 to refer to the appropriate yearly release of the other
2. For draft releases, we change the name of the document to be next year with the word "draft" after the year, and refer to each other by that name

How does that sound?

[gibson042]

Sure, that seems fine.