Use Title: meta instead of explicit <h1>

Author: tantek

css-break-3/Overview.bs

@@ -1,7 +1,7 @@
-<h1>CSS Fragmentation Module Level 3</h1>
 <h2 id=tagline class="no-num no-toc">Breaking the Web, one fragment at a time</h2>
 
 <pre class='metadata'>
+Title: CSS Fragmentation Module Level 3
 Status: ED
 Work Status: Testing
 ED: https://drafts.csswg.org/css-break/