Proposal: Add `AbortSignal.timeout()` shorthand to "Fetch: Abort" article

Description

The "Fetch: Abort" article excellently explains the mechanics of AbortController and demonstrates a manual timeout using

setTimeout(() => controller.abort(), 1000)

Since aborting fetches due to time constraints is a very common use case, it would be highly beneficial for learners to also see the modern AbortSignal.timeout() method.

Proposal

I propose adding a short subsection titled ### AbortSignal.timeout() immediately following the try..catch block of the manual timeout example. This section will demonstrate the shorthand syntax and note the important distinction that it throws a TimeoutError rather than an AbortError.

開啟 5-network/04-fetch-abort/article.md 並閱讀手動 timeout 範例，尤其是 try..catch 區塊。緊接著在其後新增提議的 AbortSignal.timeout() 子章節，展示簡寫形式並說明 TimeoutError 與 AbortError 之間的差異。當文章清楚涵蓋這兩種 timeout 方法時，即表示完成。