fact: Definition make_interval_diagram {C : category} (x : C) (y : C) (f : x --> y) : diagram interval_graph C.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Limits.Graphs.Colimits UniMath.Combinatorics.StandardFiniteSets UniMath.Combinatorics.FiniteSets