message: fixed union type ToString not including member names
diff: @@ -458,7 +458,7 @@ string LogicalType::ToString() const {
  string ret = "UNION(";
  size_t count = UnionType::GetMemberCount(*this);
  for (size_t i = 0; i < count; i++) {
  - ret += UnionType::GetMemberType(*this, i).ToString();
  + ret += UnionType::GetMemberName(*this, i) + " " + UnionType::GetMemberType(*this, i).ToString();
  if (i < count - 1) {
  ret += ", ";
  }
  