Support iterator generation for methods returning structs

[Not-Dhananjay-Mishra]

gen-iterators.go currently does not generate iterators for methods that return a struct, even when those methods accept ListOptions or ListCursorOptions.

Example:

type ListSomething struct {
    Issue []Struct `json:"Issue"`
}

If a method: Accepts ListOptions or ListCursorOptions and Returns a struct that contains a slice field,
then gen-iterators.go should be able to make iterator for it.

[mohak1]

Hi, I would like to help with this if no one's already working on it

[gmlewis]

Hi, I would like to help with this if no one's already working on it

Thank you, @mohak1!
It's yours.

[gmlewis]

Please check out our CONTRIBUTING.md if you haven't submitted PRs for this repo in the past, and feel free to ask questions in this issue and someone will hopefully be able to help you out.

[mohak1]

Thanks @gmlewis, yes it's my first time contributing to this repo. I'll go through the CONTRIBUTING.md to understand the guidelines, and I'll post questions here if I'm stuck or need clarification