fact: Definition pb_of_fully_faithful_1cell_2cell : h₁ ==> h₂.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.Bicategories.Core.Bicat UniMath.Bicategories.Core.Invertible_2cells UniMath.Bicategories.Core.Examples.OpCellBicat UniMath.Bicategories.Morphisms.FullyFaithful UniMath.Bicategories.Morphisms.DiscreteMorphisms UniMath.Bicategories.Morphisms.InternalStreetFibration UniMath.Bicategories.Morphisms.InternalStreetOpFibration UniMath.Bicategories.Morphisms.Properties.Composition UniMath.Bicategories.Limits.Pullbacks UniMath.Bicategories.Limits.Examples.OpCellBicatLimits