[clang] [clang] Refactor attr diagnostics to use %select (PR #122473)

[Ilya Biryukov via cfe-commits]

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@@ -3708,9 +3709,9 @@ void Parser::ParseDeclarationSpecifiers(
             continue;
 
           if (PA.getKind() == ParsedAttr::AT_LifetimeBound)
-            Diag(PA.getLoc(), diag::err_attribute_wrong_decl_type_str)
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ilya-biryukov wrote:

Do we have any instances of `_str` versions left?

- If not, maybe remove them from the TableGen files?
- If yes, what's stopping us from replacing them with enumerations and removing them from TableGen files?

https://github.com/llvm/llvm-project/pull/122473