Go wraps cannot throw errors

**Describe the bug**
This is the generated interface for a module with a single method that returns a string:

```go
type Module interface {
    Obscure(args *ArgsObscure) string
}
```

Since errors cannot be thrown in Go, we should handle them in the bindings as with do with Rust's `Result` type:

```go
type Module interface {
    Obscure(args *ArgsObscure) (string, error)
}
```
