[cxx_status] Note that Clang has supported std::source_location since

version 9.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@374131 91177308-0d34-0410-b5e6-96231b3b80d8

www/cxx_status.html

@@ -1247,7 +1247,7 @@ and library features that are not part of standard C++.</p>
       <td>[TS] Library Fundamentals, Version 2 (<tt>source_location</tt>)</td>
      <td><a href="http://wg21.link/n4617">N4617</a></td>
       <td>N/A</td>
-      <td class="none" align="center">No</td>
+      <td class="full" align="center">Clang 9 (<a href="docs/LanguageExtensions.html#source-location-builtins">documentation</a>)</td>
     </tr>
     <tr>
       <td>[TS] Modules</td>