[clang] [compiler-rt] [llvm] [libcxx] Use debug() instead of note() for substitutions and features (PR #193667)

[Nikolas Klauser via cfe-commits]

https://github.com/philnik777 approved this pull request.

With the title and description updated I'm fine with not printing the substitutions by default.

https://github.com/llvm/llvm-project/pull/193667