Argument name of BlackBoxContinuousSystem in `@ivp` is ignored

[schillic]

I would expect the following to fail:

julia> using MathematicalSystems
julia> f(u) = 1;  # irrelevant, just needs to be defined
julia> U0 = [1];  # irrelevant, just needs to be defined
julia> @ivp(u' = f(xxx), u(0) ∈ U0, dim:1)  # `xxx` should be `u`
InitialValueProblem{BlackBoxContinuousSystem{typeof(f)}, Vector{Int64}}(BlackBoxContinuousSystem{typeof(f)}(f, 1), [1])