[Suggestion]: Add some elaboration to the docs for TypeScript DOM events and Pure Functions

Summary

The Section on DOM events in the page Using TypeScript, mentions extracting functions, this can be elaborated further to include the case where we do get the types i.e. inline methods.

The section on Pure Functions contain a example of Teacups and guests, the global let guests variable should be incremented by 1, but is incremented by 2. Since, React is running in StrictMode for development, this might be confusing for newbies. Found here: https://react.dev/learn/keeping-components-pure#side-effects-unintended-consequences
Edit: The deep dive for this chapter contains the explanation.

Page

https://react.dev/learn/keeping-components-pure

Details

Add another small example where it shows that we do get types when using inline methods, to make it more clear.

Either turn off Strict mode for this example OR explain why we are getting 2, 4, 6 instead of the expected 1, 2, 3 because of React.StrictMode.

開啟連結的 keeping-components-pure 頁面和 Using TypeScript 區段，然後找到有關擷取函式的 DOM 事件討論。加入一個簡短的內嵌方法範例，說明事件型別會被推斷出來，並確認該說明對初學者來說清楚易懂。