extensions/references-view/src/types/index.ts/RichTypesDirection/constructor
class RichTypesDirection:	constructor(
		private _mem: vscode.Memento,
		private _value: TypeHierarchyDirection = TypeHierarchyDirection.Subtypes,
	) {
		const raw = _mem.get<TypeHierarchyDirection>(RichTypesDirection._key);
		if (typeof raw === 'string') {
			this.value = raw;
		} else {
			this.value = _value;
		}
	}