Pass description through flatten()

Author: hersle

src/systems/diffeqs/odesystem.jl

@@ -398,6 +398,7 @@ function flatten(sys::ODESystem, noeqs = false)
             discrete_events = discrete_events(sys),
             defaults = defaults(sys),
             name = nameof(sys),
+            description = get_description(sys),
             initialization_eqs = initialization_equations(sys),
             is_dde = is_dde(sys),
             checks = false)