[clang] [Clang] [C++26] Implement P2573R2: `= delete("should have a reason");` (PR #86526)

[Mariya Podchishchaeva via cfe-commits]

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@@ -873,9 +873,14 @@ void DeclPrinter::VisitFunctionDecl(FunctionDecl *D) {
 
   if (D->isPureVirtual())
     Out << " = 0";
-  else if (D->isDeletedAsWritten())
+  else if (D->isDeletedAsWritten()) {
     Out << " = delete";
-  else if (D->isExplicitlyDefaulted())
+    if (const auto *M = D->getDeletedMessage()) {
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Fznamznon wrote:

Could you please spell out the type?
```suggestion
    if (const StringLiteral *M = D->getDeletedMessage()) {
```

https://github.com/llvm/llvm-project/pull/86526