gh-35683: deprecation warning for #34880
Per https://github.com/sagemath/sage/pull/34962#issuecomment-1563801511,
we should first issue deprecation warnings for the change suggested in
#34880.
URL: https://github.com/sagemath/sage/pull/35683
Reported by: Lorenz Panny
Reviewer(s): Kwankyu Lee
