debug: printing of the DiffSolver name

Author: franckgaga

src/model/nonlinmodel.jl

@@ -152,7 +152,7 @@ julia> f!(ẋ, x, u, _ , p) = (ẋ .= p*x .+ u; nothing);
 julia> h!(y, x, _ , _ ) = (y .= 0.1x; nothing);
 
 julia> model1 = NonLinModel(f!, h!, 5.0, 1, 1, 1, p=-0.2)       # continuous dynamics
-NonLinModel with a sample time Ts = 5.0 s, RungeKutta{4} solver and:
+NonLinModel with a sample time Ts = 5.0 s, RungeKutta(4) solver and:
  1 manipulated inputs u
  1 states x
  1 outputs y
@@ -307,5 +307,8 @@ h!(y0, model::NonLinModel, x0, d0, p) = model.h!(y0, x0, d0, p)
 
 include("solver.jl")
 
-detailstr(model::NonLinModel) = ", $(typeof(model.solver)) solver"
-detailstr(::NonLinModel{<:Real, <:EmptySolver}) = ", empty solver"
+function detailstr(model::NonLinModel{<:Real, <:RungeKutta{N}}) where N
+    return ", $(nameof(typeof(model.solver)))($N) solver"
+end
+detailstr(::NonLinModel{<:Real, <:EmptySolver}) = ", empty solver"
+detailstr(::NonLinModel) = ""