src/vs/editor/common/languages/supports/inplaceReplaceSupport.ts/BasicInplaceReplace/valueSetReplace
class BasicInplaceReplace:	private valueSetReplace(valueSet: string[], value: string, up: boolean): string | null {
		let idx = valueSet.indexOf(value);
		if (idx >= 0) {
			idx += up ? +1 : -1;
			if (idx < 0) {
				idx = valueSet.length - 1;
			} else {
				idx %= valueSet.length;
			}
			return valueSet[idx];
		}
		return null;
	}