[clang] [llvm] [clang] Deduplicate builtin diagnostic descriptions (PR #202624)

[Aaron Ballman via llvm-commits]

================
@@ -111,25 +79,26 @@ struct StaticDiagInfoRec {
   uint16_t WarnNoWerror : 1;
   LLVM_PREFERRED_TYPE(bool)
   uint16_t WarnShowInSystemHeader : 1;
+  LLVM_PREFERRED_TYPE(diag::Group)
+  uint16_t OptionGroupIndex : 14;
----------------
AaronBallman wrote:

Why did this one move?

https://github.com/llvm/llvm-project/pull/202624