Generated signatures are not easy to work with

[joelburget]

1. The worst part is that they require Wrapper. We should be able to ignore this
2. val language : Lvca_syntax.Abstract_syntax.t is always required.
3. There's this awkward wrapping with the inner Ty module:

module Type : sig
  include
    [%lvca.abstract_syntax_module_sig
  {|
    sort : *

    ty := Sort(sort) | Arrow(ty; ty)
    |}
  , { sort = "Sort_model.Sort" }]

  include Nominal.Convertible.Extended_s with type t := Ty.t