[Clang] Fix status of P1774 Portable assumptions

Author: cor3ntin

clang/www/cxx_status.html

@@ -381,7 +381,7 @@ <h2 id="cxx23">C++23 implementation status</h2>
     <tr>
       <td>Portable assumptions</td>
       <td><a href="https://wg21.link/P1774R8">P1774R8</a></td>
-      <td class="full" align="center">Clang 19</td>
+      <td class="unreleased" align="center">Clang 19</td>
     </tr>
     <tr>
       <td>Support for UTF-8 as a portable source file encoding</td>