Not user-friendly error for the dimension parameter

[Nimrais]

The error is related to an incomplete specification of the Dirichlet distribution in the projection constraints, however should be the same for all distributions where the dimension specification required.

ERROR: MethodError: no method matching get_natural_manifold_base(::Type{Dirichlet}, ::Tuple{}, ::Nothing)
Closest candidates are:
  get_natural_manifold_base(::Type{Bernoulli}, ::Tuple{}, ::Any)
   @ ExponentialFamilyManifolds ~/.julia/packages/ExponentialFamilyManifolds/U3q3O/src/natural_manifolds/bernoulli.jl:6
  get_natural_manifold_base(::Type{Categorical{P} where P<:Real}, ::Tuple{}, ::Any)
   @ ExponentialFamilyManifolds ~/.julia/packages/ExponentialFamilyManifolds/U3q3O/src/natural_manifolds/categorical.jl:7
  get_natural_manifold_base(::Type{Rayleigh}, ::Tuple{}, ::Any)
   @ ExponentialFamilyManifolds ~/.julia/packages/ExponentialFamilyManifolds/U3q3O/src/natural_manifolds/rayleigh.jl:7