[clang] [clang][Sema] Fix incomplete C mode incompatible ExtInfo/ExtProtoInfo conversion diagnostic (PR #160477)

[Mariya Podchishchaeva via cfe-commits]

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@@ -10208,15 +10208,12 @@ class Sema final : public SemaBase {
                                  bool CStyle, bool &ObjCLifetimeConversion);
 
   /// Determine whether the conversion from FromType to ToType is a valid
-  /// conversion that strips "noexcept" or "noreturn" or "cfi_unchecked_callee"
-  /// off the nested function type. This also checks if "cfi_unchecked_callee"
-  /// was added to the function type. If "cfi_unchecked_callee" is added and
-  /// `AddingCFIUncheckedCallee` is provided, it will be set to true. The same
-  /// thing applies for `DiscardingCFIUncheckedCallee` if the attribute is
-  /// discarded.
-  bool IsFunctionConversion(QualType FromType, QualType ToType,
-                            bool *DiscardingCFIUncheckedCallee = nullptr,
-                            bool *AddingCFIUncheckedCallee = nullptr) const;
+  /// conversion of ExtInfo/ExtProtoInfo on the nested function type.
+  /// More precisely, this method checks whether FromType can be tranformed
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Fznamznon wrote:

```suggestion
  /// More precisely, this method checks whether FromType can be transformed
```

https://github.com/llvm/llvm-project/pull/160477