Fix markup in cxx_status.html

Author: cor3ntin

clang/www/cxx_status.html

@@ -440,7 +440,7 @@ <h2 id="cxx23">C++23 implementation status</h2>
     <tr>
       <td>Using unknown pointers and references in constant expressions</td>
       <td><a href="https://wg21.link/P2280R4">P2280R4</a></td>
-      <td class="none" align="center">Clang 20</td>
+      <td class="unreleased" align="center">Clang 20</td>
     </tr>
     <tr>
       <td>static <code>operator()</code></td>