mathlib

2c84c2c5 - feat(order/well_founded_set): `prod.lex` is well-founded (#18665)

feat(order/well_founded_set): `prod.lex` is well-founded (#18665) Co-authored-by: Junyan Xu <junyanxu.math@gmail.com> Co-authored-by: Eric Wieser <wieser.eric@gmail.com>