[clang] [APINotes] Add SWIFT_RETURNS_(UN)RETAINED support to APINotes (PR #118938)

[Gábor Horváth via cfe-commits]

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@@ -511,6 +511,10 @@ static void ProcessAPINotes(Sema &S, FunctionOrMethod AnyFunc,
       AnyTypeChanged = true;
   }
 
+  // returns_(un)retained
+  if (!Info.SwiftReturnOwnership.empty())
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Xazax-hun wrote:

There are other places where we do not validate strings. Feel free to ignore this comment. 

https://github.com/llvm/llvm-project/pull/118938