[clang] [clang] [modules] Add err_main_in_named_module (PR #146247)

[Ashwin Banwari via cfe-commits]

ashwinbanwari wrote:

It seems I need to add the line `// WARNING-NEXT: -Wmain-attached-to-named-module` on this [line](https://sourcegraph.com/github.com/llvm/llvm-project/-/blob/clang/test/Driver/autocomplete.c?L114) to fix the autocomplete test.

What is the process to amend this PR?

https://github.com/llvm/llvm-project/pull/146247