Optional fields in nested structs are omitted

[sdboyer]

The following:

Inside: {
    optional?: [...{
        bar: string
        foo?: string
    }]
} @cuetsy(kind="interface")

Should produce:

export interface Inside {
  optional?: {
    foo?: string;
    bar: string;
  }[];
}

But instead produces:

export interface Inside {
  optional?: {
    bar: string;
  }[];
}

omitting the nested foo? field.