sage

ad3f10b6 -

gh-37163: moving modular stuff to "CommutativeRing" class as a step towards simplifying old coercion framework also adding some typing annotations ### :memo: Checklist - [x] The title is concise, informative, and self-explanatory. - [x] The description explains in detail what this PR is about. URL: https://github.com/sagemath/sage/pull/37163 Reported by: Frédéric Chapoton Reviewer(s): Alex J Best