[clang] Add Documentation for Execution Results Handling in Clang-Repl (PR #65650)

[Vassil Vassilev via cfe-commits]

vgvassilev wrote:

> Actually no, that's not possible as config-ix modules are explicitly private to their subproject and should not be used outside them. I'm going to revert this change due to this layering violation.

@nikic, can you suggest a particular fix? We saw this approach was done elsewhere as well…

https://github.com/llvm/llvm-project/pull/65650