fact: Definition monoidal_struct_equiv_monoidal (C : category) : monoidal_struct C ≃ monoidal C.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Monoidal.WhiskeredBifunctors UniMath.CategoryTheory.Monoidal.Categories