Hi, i was using Trixi.jl for the Brown and Minion test case and i was trying to use the StructuredMesh function to refine the mesh cells by cells (20x20 to 25x25 and so on) but it seems that the create_cache_parabolic function is not defined for a StructuredMesh type

```
ERROR: LoadError: MethodError: no method matching create_cache_parabolic(::StructuredMesh{2, Float64}, ::CompressibleEulerEquations2D{Float64}, ::CompressibleNavierStokesDiffusion2D{GradientVariablesPrimitive, Float64, Float64, CompressibleEulerEquations2D{Float64}}, ::DGSEM{LobattoLegendreBasis{Float64, 5, SVector{5, Float64}, Matrix{Float64}, Matrix{Float64}, Matrix{Float64}}, Trixi.LobattoLegendreMortarL2{Float64, 5, Matrix{Float64}, Matrix{Float64}}, SurfaceIntegralWeakForm{typeof(flux_hllc)}, VolumeIntegralWeakForm}, ::ViscousFormulationBassiRebay1, ::Type{Float64}, ::Type{Float64})
Closest candidates are:
create_cache_parabolic(!Matched::P4estMesh{3}, ::Trixi.AbstractEquations, ::Trixi.AbstractEquationsParabolic, ::DG, ::Any, ::Any, ::Any)
@ Trixi /scratch/stg-cfds/renoux/Trixi.jl/src/solvers/dgsem_p4est/dg_3d_parabolic.jl:11
create_cache_parabolic(!Matched::P4estMesh{2}, ::Trixi.AbstractEquations, ::Trixi.AbstractEquationsParabolic, ::DG, ::Any, ::Any, ::Any)
@ Trixi /scratch/stg-cfds/renoux/Trixi.jl/src/solvers/dgsem_p4est/dg_2d_parabolic.jl:11
create_cache_parabolic(!Matched::TreeMesh{3, TreeType} where TreeType<:Trixi.AbstractTree{3}, ::Trixi.AbstractEquations, ::Trixi.AbstractEquationsParabolic, ::DG, ::Any, ::Any, ::Any)
@ Trixi /scratch/stg-cfds/renoux/Trixi.jl/src/solvers/dgsem_tree/dg_3d_parabolic.jl:986
```

On the Trixi.jl documentation, i saw that CompressibleNavierStokesEquations() should be supported for StructuredMesh

So i just wanted to know if it was a mistake on my part or just a future implementation ?