"Built-in Types" page is too long

Documentation

The Built-in Types document is very long, and as a result it basically never shows up in search engine results, because 90% of the page is considered irrelevant for any query like "python strings".

I suggest we split it up by top-level topic, e.g. we add a dedicated page for "Text Sequence Type — str"

See also #126053

首先查看 issue 中連結的 Built-in Types 頁面，以及 #126053 中的相關討論。判斷哪些頂層主題應該成為獨立頁面，包括提議的 Text Sequence Type — str 頁面。完成的標準是：文件被拆分成實用的主題頁面，同時不遺失現有的內建型別涵蓋範圍。