Clarifying documentation of typing.Set

Documentation

Edit: I added some more clarification.

Documentation of typing.Set is not entirely clear

The typing module's documentation currently requires two hops when the reader looks up typing.Set.

1. In the docstring of typing.Set it states "To annotate arguments it is preferred to use an abstract collection type such as AbstractSet." This is referring to typing.AbstractSet
2. Docstring of typing.AbstractSet says that it is deprecated and refers the reader to collections.abc.Set, which has no docstring of its own (it is grouped together with the docstring of collections.abc.MutableSet.
   I feel we can prevent these two hops i.e. typing.Set --> typing.AbstractSet --> collections.abc.Set and direct the reader to the final destination i.e. typing.Set -> collections.abc.Set.

Suggested change

1. typing.Set should say something like --

"To annotate arguments it is preferred to use an abstract collection type such as collections.abc.Set.
"To annotate everything else, the use of typing.Set is deprecated since version 3.9: builtins.set now supports []. See PEP 585 and Generic Alias Type"

2. Docstring of typing.AbstractSet is fine as it is.
3. collections.abc.Set should say something like --

"Use this to annotate arguments. For all other annotations, use builtins.set, which now supported []. See PEP 585 ...

Other generic alias types like List, Tuple, FrozenSet etc. probably could use a similar change (IF others agree that this is something that needs to changed at all.)

先從 typing.Set 和 collections.abc.Set 的文件字串開始，接著比較相關的泛型別名文件以及 PEP 585 中的指引。完成的標準是：文件將讀者從 typing.Set 直接引導至 collections.abc.Set，不再經過額外的中間步驟，並清楚說明何時使用 builtins.set。