[clang] [clang-repl] Improve error message on failed undos (PR #149396)

[David Spickett via cfe-commits]

DavidSpickett wrote:

> Do I need to do anything else?

No, all good.

> Or is squashing the commits and merging up to someone with write permissions?

GitHub will do the squashing, and yes I just clicked the merge button for you. Once you have established a track record you can [ask for permissions](https://llvm.org/docs/DeveloperPolicy.html#obtaining-commit-access) to be able to do this yourself.

At no point do you *have* to have those permissions though, so I wouldn't bother with it for a while.

> Also, thanks a lot for the help. I plan to find a new issue to work on soon.

If you want to stay around clang-repl, I opened https://github.com/llvm/llvm-project/issues/143666 around the same time. Feel free to pick anything else of interest though.

https://github.com/llvm/llvm-project/pull/149396