[clang] [Clang] enhance diagnostic message for __builtin_bit_cast size mismatch (PR #115940)

[Aaron Ballman via cfe-commits]

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@@ -528,6 +528,8 @@ Improvements to Clang's diagnostics
 
 - Clang now diagnoses ``[[deprecated]]`` attribute usage on local variables (#GH90073).
 
+- Improved diagnostic message for __builtin_bit_cast size mismatch (#GH115870).
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AaronBallman wrote:

```suggestion
- Improved diagnostic message for ``__builtin_bit_cast`` size mismatch (#GH115870).
```

https://github.com/llvm/llvm-project/pull/115940