[selectors] Universal selector missing from grammar

[tim-loh]

The universal selector (i.e. *) is missing from the selectors spec's grammar.

https://drafts.csswg.org/selectors/#grammar

[SelenIT]

Agree. Even if the spec defines it as 'a special type selector' (which kind of makes sense, although might be confusing regarding different specificity), shouldn't its formal grammar be <type-selector> = <wq-name> | <ns-prefix>? '*' (with optional namespece token) instead of <type-selector> = <wq-name> | <ns-prefix> '*'?