fact: Definition monoidal_to_monoidal_struct {C : category} (M : monoidal C) : monoidal_struct C.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Monoidal.WhiskeredBifunctors UniMath.CategoryTheory.Monoidal.Categories