[clang] [clang] C++20 Modules: document how to perform automated reductions (PR #124997)

[via cfe-commits]

https://github.com/cor3ntin requested changes to this pull request.

This is an excellent idea.

But I think this needs to be a bit more specific and describe how to write an interestingness test specific to modules.

(I thought we had non-modules documentation for creduce but apparently not)

https://github.com/llvm/llvm-project/pull/124997