87da62028e
This aligns `ClangDiagnosticManagerAdapter` with how we set up the diagnostics in `ClangModulesDeclVendor`. We fixed lifetime issues around the same kind of setup here: https://github.com/llvm/llvm-project/pull/167724 This class didn't suffer from the same lifetime issue because it used `shared_ptr`s. So the stream wasn't freed before `~TextDiagnosticPrinter` accessing it. But that begged the question of why these are `shared_ptr`s in the first place. This patch makes these `unique_ptr`s and fixes the destruction order that would now be an issue.