[clang] [Clang] Add -Wcounted-by-addrof to warn when &fam discards __counted_by (PR #206760)

[Aaron Ballman via cfe-commits]

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@@ -1870,6 +1870,7 @@ def NoDeref : DiagGroup<"noderef">;
 // -fbounds-safety and bounds annotation related warnings
 def BoundsSafetyCountedByEltTyUnknownSize :
   DiagGroup<"bounds-safety-counted-by-elt-type-unknown-size">;
+def CountedByAddrof : DiagGroup<"counted-by-addrof">;
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AaronBallman wrote:

Are we going to be adding more diagnostics to this group (or this group to other groups)? If not, you can back this change out and define the group inline  with the diagnostic.

https://github.com/llvm/llvm-project/pull/206760