Support Chinese in html permalink href

[StageDog]

Is your feature request related to a problem? Please describe.
html permalinks in Chinese docs are not permanent.
For example, given a <h2> titled as "调试方法", sphinx might generate a href="id3" for it; when I insert some <h2>s before it, "调试方法" goes to href="id6" or href="id{x}".
In a result, I'm always frustrated that I can't share my audience a permanent link that jumps to the exact section while keeping updating my docs.

docs generated by Sphinx fail to include Chinese into href ids

https://sillytavern-stage-girls-dog.readthedocs.io/工具经验/角色阶段/#id8

docs generated by Vitepress work well

https://n0vi028.github.io/JS-Slash-Runner-Doc/guide/关于酒馆助手/介绍.html#酒馆助手-tavern-helper

Describe the solution you'd like
Put Chinese in headings and figure captions into their href ids.

Describe alternatives you've considered
If this is not resolved, I may have to reluctantly migrate to other documentation tools.

[AA-Turner]

Do you have a minimal reproducer? No member of the core team speaks Chinese, so we will need some help here.

A

[StageDog]

Do you have a minimal reproducer? No member of the core team speaks Chinese, so we will need some help here.

A

sphinx-build . build on sample.zip

[AA-Turner]

Plain text:

.. index.rst 

测试
==========

``href`` of the above heading is ``id1``.


测试2
----------

``href`` of the above heading is ``id2``.


测what试
----------

``href`` of the above heading is ``what``.

# conf.py
language = 'zh_CN'

[gmilde]

This is a duplicate of #8709 (at least in the sense, that auto-generated IDs are used in the section "self-link" because of Docutils ID generation rules).

The next version of Docutils should definitely try to solve this issue.