添加对 `Box<T>` 的支持

如果我有以下结构体：

#[derive(Debug, Serialize, Deserialize, Apiv2Schema)]
pub struct Foo {
     pub elements: Vec<Box<Foo>>,
}

我会得到以下错误：

9 | #[derive(Debug, Serialize, Deserialize, Apiv2Schema)]
  |                                         ^^^^^^^^^^^ function or associated item cannot be called on `std::vec::Vec<std::boxed::Box<Foo>>` due to unsatisfied trait bounds
  |
  = note: the following trait bounds were not satisfied:
          `&std::vec::Vec<std::boxed::Box<Foo>>: paperclip::v2::schema::TypedData`
          which is required by `&std::vec::Vec<std::boxed::Box<Foo>>: paperclip::v2::schema::Apiv2Schema`
          `&mut std::vec::Vec<std::boxed::Box<Foo>>: paperclip::v2::schema::TypedData`
          which is required by `&mut std::vec::Vec<std::boxed::Box<Foo>>: paperclip::v2::schema::Apiv2Schema`
  = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
error: aborting due to previous error

我认为问题来自 Box 部分，因为 Vec<T> 通常会正确处理。我将尝试查看核心代码，看看是否可以打开一个 Pull Request，但如果有人知道如何解决这个问题，我会很乐意接受。