parser coordinate x, y based on point

[luxebeng]

there is an Todo issue for point, need to parser point coordinate x, y. then x, y can be stored into transcript separately.

    public fun common_point(self: &mut Transcript, point: Element<G1>) {
        hasher::update(&mut self.state, vector::singleton(KECCAK256_PREFIX_POINT));

        // Fixme. here need write coordinate x and y seperately?
        let p = bn254_arithmetic::to_bytes<G1, FormatG1Compr>(&point);
        hasher::update(&mut self.state, p)
        // let (x, y) = point::coordinates(&point);
        // hasher::update(&mut self.state, x);
        // hasher::update(&mut self.state, y);
    }