first-reference-note-number should consider containers

[Tomagori]

Currently first-reference-note-number triggers when the same item is referenced again. However, when working with legal commentaries, I extensively utilise CSL-M's container tracking feature, specifically position="container-subsequent", which first-reference-note-number ignores.

Ideally, first-reference-note-number would not only be triggered when citing the same item again (linking back to the first occurrence of this item), but also when citing the same container again (linking back to the first occurrence of this container).