Guidance for doing my first contribution

I had some fiddling around with build errors having to do with the Llvm_debuginfo module, but now I’ve updated my patch with tests!

According to Code Reviews with Phabricator — LLVM 16.0.0git documentation, In addition to pinging the code owner, I should find people who recently touched the part of the code I was working on to be code reviewers. Since I’m not sure who the code owner is, I’m going to do the latter…