[css-contain] Do container names really need to be deduplicated, but only at computed-value time? #7181
Description
If we take https://andreubotella.com/csswg-auto-build/css-contain-3/#container-name to the letter, the specified value would need to have duplicates, but the computed value wouldn't.
I don't think we have many precedents for such a thing, is there any reason the container-name can't just rename as specified?
Also, if it needs to be deduplicated for some reason, why not doing it at parse time?