In this module an ObjC interface declaration is processed. The class is saved in the tenv as a struct with the corresponding fields, potential superclass and list of defined methods

`val interface_declaration : CAst_utils.qual_type_to_sil_type ‑> CAst_utils.procname_from_decl ‑> InferIR.Tenv.t ‑> InferGenerated.Clang_ast_t.decl ‑> InferIR.Typ.desc`
`val interface_impl_declaration : CAst_utils.qual_type_to_sil_type ‑> CAst_utils.procname_from_decl ‑> InferIR.Tenv.t ‑> InferGenerated.Clang_ast_t.decl ‑> InferIR.Typ.desc`