[clang-tools-extra] [clangd] [C++20] [Modules] Introduce initial support for C++20 Modules (PR #66462)

[Ilya Biryukov via cfe-commits]

ilya-biryukov wrote:

I'm Sam's colleague and wanted to mention that Sam won't be available until January 15.
It probably does not make much sense for someone else to take over at this point as the change is large and waiting for Sam is more efficient than ramping up someone else at this point.

Sorry about the delays.

https://github.com/llvm/llvm-project/pull/66462