message: Fixed the ptr.rs comments having compiler errors.
diff: @@ -36,6 +36,9 @@ pub struct Item;
  /// This type can also be used with primitive-filled structs, but be careful of
  /// guarantees required by `ValueType`.
  /// ```
  +/// # use wasmer::Memory;
  +/// # use wasmer::WasmPtr;
  +///
  /// #[derive(Copy, Clone, Default)]
  /// #[repr(C)]
  /// struct V3 {
  