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

[Aaron Ballman 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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AaronBallman wrote:

We don't typically document anything which the compiler isn't required to provide (for example, we don't really list other things from the C standard library). We could add an `N/A` status like we have for DRs, but I think that would start to drown out the relevant information due to talking about editorial changes as well as library changes.

WDYT?

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