sage

51616659 -

gh-36934: details fixed in cfinite_sequence.py fixing a few details in C-finite sequences main change : use `Parent` (new coercion framework) instead of `Ring` ### :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/36934 Reported by: Frédéric Chapoton Reviewer(s): Matthias Köppe