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

[Nikita Popov via cfe-commits]

nikic wrote:

You probably should just use find_program instead of llvm_find_program. It looks like llvm_find_program is used in just a single place, while we have very wide direct use of find_program, so I'm not sure why it is a thing in the first place.

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