Issue on docs

Not found function in 3.0

<img width="548" height="76" alt="Image" src="https://github.com/user-attachments/assets/7634b8d8-0793-4494-8ca6-9240208795ae" />

Path:/zh-CN/docs/3.0/sql-manual/sql-functions/scalar-functions/string-functions/count_substrings