regenerate docs.

doc/html/index.html

@@ -1,6 +1,6 @@
 <html>
 <head>
-<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 <title>Boost.Config</title>
 <link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css">
 <meta name="generator" content="DocBook XSL Stylesheets V1.79.1">
@@ -26,7 +26,7 @@
 <div><div class="authorgroup"><div class="author"><h3 class="author">
 <span class="firstname">Vesa Karvonen, John Maddock</span> <span class="surname">Beman Dawes</span>
 </h3></div></div></div>
-<div><p class="copyright">Copyright &#169; 2001-2007 Beman Dawes, Vesa Karvonen, John
+<div><p class="copyright">Copyright © 2001-2007 Beman Dawes, Vesa Karvonen, John
       Maddock</p></div>
 <div><div class="legalnotice">
 <a name="config.legal"></a><p>
@@ -990,7 +990,7 @@
 </div>
 </div>
 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
-<td align="left"><p><small>Last revised: March 23, 2020 at 21:06:56 GMT</small></p></td>
+<td align="left"><p><small>Last revised: June 23, 2020 at 17:55:32 GMT</small></p></td>
 <td align="right"><div class="copyright-footer"></div></td>
 </tr></table>
 <hr>