How to make clangd in Zed Editor recognize that I'm using C++20 standard code so it doesn't show errors [closed]

Platform: Windows 11

It is a single-file project, and I haven't used CMake or other build tools — I compile the code manually with g++ myself.

I tried creating a .clangd file in the root directory of the repository and input the content:

However, it doesn't seem to have any effect at all.