feat(algebra/order/monoid_lemmas_zero_lt): more lemmas using `pos_mul` and friends (#12355)
feat(algebra/order/monoid_lemmas_zero_lt): more lemmas using `pos_mul` and friends (#12355)

This PR continues the `order` refactor.  The added lemmas are the `\le` analogues of the `<` lemmas that are already present.





leanprover-community/mathlib,leanprover-community/mathlib