add to cxx_status

Author: kish1n

clang/www/cxx_status.html

@@ -935,7 +935,7 @@ <h2 id="cxx20">C++20 implementation status</h2>
       </tr>
       <tr>
         <td><a href="https://wg21.link/p2115r0">P2115R0</a></td>
-        <td class="partial" align="center">Partial</td>
+        <td class="full" align="center">Yes</td>
       </tr>
       <tr>
         <td><a href="https://wg21.link/p1815r2">P1815R2</a></td>