[css-scoping] Always serialise the implicit `:scope` ?

[mdubet]

For the css-nesting spec, we resolved to always serialise the implicit &:

When serializing a relative selector in a nested style rule, the selector must be absolutized, with the implied nesting selector inserted.

https://drafts.csswg.org/css-nesting/#cssom

Should we do the same for the implicit :scope in scoped style rule ?

They accept a relative-selector-list as their prelude (rather than just a selector-list). Such relative selectors are relative to :scope.