std::linalg::setup_givens_rotation_result(C++26)

namespace std::linalg {
  template<class Real>
  struct setup_givens_rotation_result {
    Real c;
    Real s;
    Real r;
  };

  template<class Real>
  struct setup_givens_rotation_result<complex<Real>> {
    Real c;
    complex<Real> s;
    complex<Real> r;
  };
}