src/vs/editor/contrib/smartSelect/browser/smartSelect.ts/SelectionRanges/mov
class SelectionRanges:	mov(fwd: boolean): SelectionRanges {
		let index = this.index + (fwd ? 1 : -1);
		if (index < 0 || index >= this.ranges.length) {
			return this;
		}
		const res = new SelectionRanges(index, this.ranges);
		if (res.ranges[index].equalsRange(this.ranges[this.index])) {
			// next range equals this range, retry with next-next
			return res.mov(fwd);
		}
		return res;
	}