[clang] [Clang] Diagnose UB and emit error when identifier has both internal and external linkage (PR #192116)

[Aaron Ballman via cfe-commits]

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@@ -283,7 +283,7 @@ <h2 id="c2y">C2y implementation status</h2>
     <tr>
       <td>Slay Some Earthly Demons XI</td>
       <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3410.pdf">N3410</a></td>
-      <td class="none" align="center">No</td>
+      <td class="full" align="center">Yes</td>
----------------
AaronBallman wrote:

```suggestion
      <td class="unreleased" align="center">Clang 23</td>
```

https://github.com/llvm/llvm-project/pull/192116