src/vs/workbench/contrib/typeHierarchy/browser/typeHierarchyTree.ts/AccessibilityProvider/getAriaLabel
class AccessibilityProvider:	getAriaLabel(element: Type): string | null {
		if (this.getDirection() === TypeHierarchyDirection.Supertypes) {
			return localize('supertypes', "supertypes of {0}", element.item.name);
		} else {
			return localize('subtypes', "subtypes of {0}", element.item.name);
		}
	}