src/vs/editor/common/core/position.ts/Position/isBefore
class Position:	public static isBefore(a: IPosition, b: IPosition): boolean {
		if (a.lineNumber < b.lineNumber) {
			return true;
		}
		if (b.lineNumber < a.lineNumber) {
			return false;
		}
		return a.column < b.column;
	}