[clang] [C23] Implement N3018: The constexpr specifier for object definitions (PR #73099)

[Aaron Ballman via cfe-commits]

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@@ -208,6 +208,7 @@ C23 Feature Support
 
 - Clang now supports ``<stdckdint.h>`` which defines several macros for performing
   checked integer arithmetic. It is also exposed in pre-C23 modes.
+- Clang now supports ``N3018 The constexpr specifier for object definitions``.
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AaronBallman wrote:

```suggestion
- Clang now supports `N3018 The constexpr specifier for object definitions <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3018.htm>`_.
```

https://github.com/llvm/llvm-project/pull/73099