Update the C status page for N3409

This was implemented in b19ed9c but I
forgot to update the website at the same time.

Author: AaronBallman

clang/www/c_status.html

@@ -284,7 +284,7 @@ <h2 id="c2y">C2y implementation status</h2>
     <tr>
       <td>Slay Some Earthly Demons X</td>
       <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3409.pdf">N3409</a></td>
-      <td class="unknown" align="center">Unknown</td>
+      <td class="unreleased" align="center">Clang 21</td>
 	</tr>
     <tr>
       <td>Slay Some Earthly Demons XI</td>