incorrect anchor in python3.9

# Documentation style bug

## Summary

bad anchor in glossary
## Actual style
python (3.9) glossary entry [f-string](https://devdocs.io/python~3.9/glossary#term-f-string) has a link to [formatted string literals](https://devdocs.io/python~3.9/reference/lexical_analysis#f-strings) with anchor `#f-strings` which doesn't scroll to any section because it's not present.

## Expected style

anchor `index-24` is needed to go to the correct section:
https://devdocs.io/python~3.9/reference/lexical_analysis#index-24

首先，使用 issue 中的 URL 作为入口，定位 Python 3.9 的 f-string 术语表条目及其链接的 lexical_analysis 部分。验证当前目标锚点，并将链接更新为 index-24；完成的标准是术语表链接能够跳转到「formatted string literals」部分。

由索引模型根据 Issue 内容生成。