Make deltaPhi and deltaR const
I'd like to use the deltaPhi function here on a const Amg::Vector3D member of SCTinformation (https://gitlab.cern.ch/atlas/athena/-/blob/21.9/InnerDetector/InDetRecTools/SiSpacePointTool/SiSpacePointTool/SCTinformation.h#L36), for which it has to be const, matching the other functions here (eg phi, eta). I'd have thought this won't cause problems, or if so that the CI will pick them up...
If this is a bad idea for reasons I've overlooked then so be it!