Generator: does not seem to use opened modules

[Cjen1]

If I have two files as follows:

a.ml

module Foo = struct
type value = int [@@deriving protobuf {protoc }

and b.ml

open A
type value2 = Foo.value
type value3 = {value: value2} [@@deriving protobuf {protoc}]

the generated protobuffer for b will be approximately:

import "A.Foo.protoc"
message value2 {
  required Foo.value _ = 1;
}

message value3 {
  required value2 value = 1;
}

This however won't compile since Foo.value is undefined, but A.Foo.value is defined.

If in b.ml:

type value2 = A.Foo.value

Then A.Foo.value is generated instead.

My suggestion would be to just amend the readme to fix this if a more correct fix is not possible.