[clang] [clang] Improve `_Alignas` on a `struct` declaration diagnostic (PR #65638)

[via cfe-commits]

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@@ -27,6 +27,7 @@
 #include "clang/AST/Randstruct.h"
 #include "clang/AST/StmtCXX.h"
 #include "clang/Basic/Builtins.h"
+#include "clang/Basic/DiagnosticSema.h"
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cor3ntin wrote:

I don't think adding this header is necessary

https://github.com/llvm/llvm-project/pull/65638