message: Update index.html
  Link /doc/filters from index.
diff: @@ -166,7 +166,7 @@ h2 {
  <p>
  The PageSpeed Modules, <a href="https://github.com/apache/incubator-pagespeed-mod" target="_blank">mod_pagespeed</a> and
  <a href="https://github.com/apache/incubator-pagespeed-ngx" target="_blank">ngx_pagespeed</a>, are open-source
  - webserver modules that optimize your site automatically.
  + webserver modules that <a href="/doc/filters">optimize your site automatically</a>.
  </p>
  <div id=resources>
  