Custom alias for slice produces empty struct instead of slice

[kukymbr]

Version of zenrpc: v2.2.12

Steps to reproduce

1. Create a custom type representing a slice of some items, for example:

   type ValidationErrors []ValidationError

2. Create an endpoint definition func returning the custom type:

   func (srv Service) Validate(ctx context.Context, req Request) (ValidationErrors, error) { }

3. Generate go client using the RPCGen.GoClient()

Expected result

Generated function for an endpoint returns a custom type representing a slice of items or a slice of items directly.

Actual result

Generated function for an endpoint returns a custom type representing an empty struct:

type ValidationErrors struct {
}