[css-inline-3] improve headings

Author: fantasai

css-inline-3/Overview.bs

@@ -966,7 +966,7 @@ Line Spacing: the 'line-height' property</h3>
 	and <a href="https://github.com/w3c/csswg-drafts/issues/2165">Issue 2165</a>.
 
 <h3 id="text-edges">
-Inline Box Edge Metrics</h3>
+Inline Box Edge Metrics: the 'text-edge' property</h3>
 	<pre class="propdef">
 	Name: text-edge
 	Value: leading | [ text | cap | ex | ideographic | ideographic-ink ] [ text | alphabetic | ideographic | ideographic-ink ]?
@@ -1155,7 +1155,7 @@ Logical Height Contributions of Inline Boxes</h3>
 	is ignored when sizing the line box.
 
 <h3 id="leading-trim">
-Half-Leading Control</h3>
+Half-Leading Control: the 'leading-trim' property</h3>
 
 	To ensure consistent spacing in the basic case of running text,
 	CSS line layout introduces leading both above and below