A bug?

I started some cleaning of my tests for rational transfer functions. The following fails and was commented out for `RationalTransferFunctions`. It seems however, it doesn't work for `RationalFunctions` too.
```
julia> using LinearAlgebra

julia> using Polynomials

julia> s = RationalFunction(Polynomial([0,1],:s))
(s) // (1)

julia> [s^2 s/(s+1); I]
ERROR: ArgumentError: number of columns of each array must match (got (2, 1))
Stacktrace:
[1] _typed_vcat(#unused#::Type{Any}, A::Tuple{Matrix{Any}, Matrix{Any}})
@ Base .\abstractarray.jl:1553
[2] typed_vcat(::Type{Any}, ::Matrix{Any}, ::Matrix{Any})
@ Base .\abstractarray.jl:1567
[3] typed_hvcat(::Type{Any}, ::Tuple{Int64, Int64}, ::RationalFunction{Int64, :s, Polynomial{Int64, :s}}, ::Vararg{Any, N} where N)
@ Base .\abstractarray.jl:1957
[4] hvcat(::Tuple{Int64, Int64}, ::RationalFunction{Int64, :s, Polynomial{Int64, :s}}, ::Vararg{Any, N} where N)
@ Base .\abstractarray.jl:1932
[5] top-level scope
@ REPL[4]:1
```