"Data model" page is too long

Documentation

The Data model 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 __hash__".

I suggest we split it up by top-level topic, e.g. we add a dedicated page for "Special method names".

See also #126052

首先查看 docs.python.org/3/reference/datamodel.html 中的 Data model 文件以及相關 issue #126052。確定頂層主題的劃分，包括一個專門的 Special method names 頁面，然後更新文件結構和連結，讓每個主題都能被獨立找到。