[Suggestion]: Make clear why Ref was used in the third solution

Summary

The solution for the third challenge, "Fix debouncing," does not require a Ref. Moving the let timeoutID; to the top inside the DebouncedButton component will fix the debouncing. Either point this out in the explanation or make it re-render so the solution requires Ref.

Page

https://react.dev/learn/referencing-values-with-refs

Details

Since code example does not use State, there's no re-rendering, and so there's no need to use Ref to remember anything across re-renders. The page mentions that Refs are not used often; although future-proof, I think the example should only use Ref when necessary.

從「Referencing Values with Refs」頁面開始，檢查第三個挑戰「Fix debouncing」，包括其說明與解決方案。完成的標準是文件解釋為什麼使用 Ref，或修改範例，讓重新渲染成為必須使用 Ref 的原因；驗證渲染後的頁面和挑戰的措辭。