[Clang] Mark consteval as supported in Clang 15 [NFC]

Support was completed by D119646.

Author: cor3ntin

clang/www/cxx_status.html

@@ -1120,11 +1120,7 @@ <h2 id="cxx20">C++20 implementation status</h2>
     <tr>
       <td rowspan=2>Immediate functions (<tt>consteval</tt>)</td>
       <td><a href="https://wg21.link/p1073r3">P1073R3</a></td>
-      <td class="partial" align="center">
-        <details><summary>Partial</summary>
-          Using consteval functions as default parameters is not yet supported.
-        </details>
-      </td>
+      <td class="unreleased" align="center">Clang 15</td>
     </tr>
       <tr> <!-- from Prague -->
         <td><a href="https://wg21.link/p1937r2">P1937R2</a></td>