GenStruct and GenEnum are missing methods to add generic parameters to the struct/enum

[NightEule5]

I would like to generate a struct or enum which inherits the generic parameters of the target type:

#[derive(MyDerive)]
struct Struct<'a, T> {
    // ...
}

#[derive(MyDerive)]
enum Enum<'a, T> {
    // ...
}

// generates:

struct OtherStruct<'a, T> {
    // ...
}

enum OtherEnum<'a, T> {
    // ...
}

But currently there is no way to add generic parameters to the generated types.