mathlib

77615d00 - chore(data/seq/*): `cases_on` → `rec_on` (#15843)

chore(data/seq/*): `cases_on` → `rec_on` (#15843) We rename recursion principles on `Sort` from `cases_on` to `rec_on`. Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>