pub fn directed_angle2<S>(
    center: Point2D<S, UnknownUnit>,
    a: Point2D<S, UnknownUnit>,
    b: Point2D<S, UnknownUnit>,
) -> Swhere
    S: Scalar,pub fn directed_angle2<S>(
    center: Point2D<S, UnknownUnit>,
    a: Point2D<S, UnknownUnit>,
    b: Point2D<S, UnknownUnit>,
) -> Swhere
    S: Scalar,