Function validate_same_loop 

pub fn validate_same_loop<S: Scalar>(
    model: &Model<S>,
    coedge1: CoedgeId,
    coedge2: CoedgeId,
) -> GeopResult<()>

Validates that coedge2 lies on the loop traced by following next from coedge1 (i.e. they bound the same face boundary loop).