Editorial: align with JavaScript spec conventions on records

[domenic]

The latest work on the JS spec seems to say things like "Let completion be Completion Record { [[Type]]: ..., [[Value]]: ..., [[Target]]: ... }."

It looks like we sometimes use Completion { with no link (should be Completion Record { with a link) and Property Descriptor{ with a link (should have a space before {).

For "untyped" records, we mostly don't have any prefix. Sometimes we have Record { linked, sometimes we have Record { unlinked, most times we just use {. Some of these these are just omitting Property Descriptor {, which we should fix. But I don't think we should necessarily add Record { in front of all of them, even though the JS spec does. It's verbose and many of these could probably be converted to Infra maps anyway. (#8363) I'm inclined to leave most of them as-is, or maybe just remove the Record prefix.