[css-overflow-3] Shorten section title

Author: fantasai

css-overflow-3/Overview.bs

@@ -431,7 +431,7 @@ Scrolling Origin, Direction, and Restriction</h3>
 	The viewport uses the <a>principal writing mode</a> for these calculations.
 
 <h2 id="max-lines">
-Limiting Number of Visible Text Lines: the 'max-lines' property</h2>
+Limiting Visible Lines: the 'max-lines' property</h2>
 
 	<pre class=propdef>
 		Name: max-lines