fact: Definition J_2_1_comp {a b : B} {f : a --> b} : J_2_1 (id2_invertible_2cell f) = r a b f.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Groupoids UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Univalence UniMath.CategoryTheory.Core.Isos UniMath.Bicategories.Core.Bicat UniMath.Bicategories.Core.Unitors UniMath.Bicategories.Core.Invertible_2cells UniMath.Bicategories.Morphisms.Adjunctions UniMath.Bicategories.Core.BicategoryLaws