[clang] [Docs] Document freestanding requirements (PR #132232)

[A. Jiang via cfe-commits]

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@@ -534,11 +534,6 @@ <h2 id="c2x">C23 implementation status</h2>
       <td class="full" align="center">Clang 16</td>
     </tr>
     <!-- Apr 2021 Papers -->
-    <tr>
-      <td>String functions for freestanding implementations</td>
-      <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2524.htm">N2524</a></td>
-      <td class="none" align="center">No</td>
-    </tr>
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frederick-vs-ja wrote:

Although the PR description said:

> This also updates the C status page to make it clear that we don't have anything to do for WG14 N2524 which adds string interfaces to freestanding mode.

It seem to me that the status will become less clear due to removal of the entry.

https://github.com/llvm/llvm-project/pull/132232