Use Title: meta instead of explicit <h1>

Author: tantek

css-ui-4/Overview.bs

@@ -1,6 +1,5 @@
-<h1>CSS Basic User Interface Module Level 4</h1>
-
 <pre class='metadata'>
+Title: CSS Basic User Interface Module Level 4
 ED: https://drafts.csswg.org/css-ui-4/
 Status Text: This specification will include and extend <cite>CSS Basic User Interface Module Level&nbsp;3.</cite> [[CSS-UI-3]]
 TR: https://www.w3.org/TR/css-ui-4/