Use Title: meta instead of explicit <h1>

Author: tantek

css-page-floats-3/Overview.bs

@@ -1,6 +1,5 @@
-<h1>CSS Page Floats</h1>
-
 <pre class='metadata'>
+Title: CSS Page Floats
 TR: https://www.w3.org/TR/css-page-floats-3/
 Status Text: Some of the features in this draft were previously published in <cite>CSS Generated Content for Paged Media Module</cite> [[CSS3GCPM]].
 Shortname: css-page-floats