bug: Category called "Function" instead of "Method" within a class.

[damskii9992]

Description of the bug

group_by_category within a class groups methods as "Functions" so when used with show_category_heading the headings become "Functions" instead of "Methods" as they should be.

To Reproduce

 ```
 git clone https://github.com/easyscience/imaging-lib/tree/documentation
 cd imaging-lib
 pixi install
 pixi docs-serve
 ```

Expected behavior

I expect the group headings to be called "Methods" instead of "Functions" when the group exists within a class.

[pawamoy]

Thanks for the report @damskii9992, I was able to confirm the issue. Moving to the mkdocstrings-python repository.

[pawamoy]

Fixed in 2.0.4 🙂