Localize an item's subtype label, falling back to the raw subtype value when no localization entry exists.
The item's subtype value (empty when the item has none).
The item kind, used as the localization-key prefix.
The localized label, the raw subtype if unlocalized, or "" when there is no subtype.
""
Localize an item's subtype label, falling back to the raw subtype value when no localization entry exists.