[clang] [llvm] [clang] report inlining decisions with -Wattribute-{warning|error} (PR #73552)

[Nick Desaulniers via cfe-commits]

nickdesaulniers wrote:

Note to reviewers, I imported this to a GH PR from https://reviews.llvm.org/D141451, and addressed comments from https://reviews.llvm.org/D141451#4311399 down.

I did have a related RFC, but the [proposal](https://discourse.llvm.org/t/rfc-improving-clangs-middle-and-back-end-diagnostics/69261/16?u=nickdesaulniers) from @rnk is a yak shave that I don't intend to pursue.

Upon rereviewing https://reviews.llvm.org/D141451, it seems there was just some minor nits to resolve.  Bringing this back up because @kees reminded me how painful this is.

https://github.com/llvm/llvm-project/pull/73552