mathlib3

2dbf5508 - feat(ring_theory/eisenstein_criterion): Eisenstein's criterion (#2946)

feat(ring_theory/eisenstein_criterion): Eisenstein's criterion (#2946) Co-authored-by: Chris Hughes <33847686+ChrisHughes24@users.noreply.github.com> Co-authored-by: Johan Commelin <johan@commelin.net>