[css-text-4] Allow truncating to N lines, per w3c#2809 (comment)

Author: fantasai

css-text-4/Overview.bs

@@ -551,12 +551,9 @@ Hyphens: the 'hyphenate-character' property</h3>
 		<dd>
 			Specifies the string that appears
 			at the end of the line before a hyphenation break.
-			The UA <em>may</em> truncate the <!-- computed value | used value --> string
-			to a single <a>typographic character unit</a>.
-<!-- alternately:
+			The UA <em>may</em> truncate the <a>used value</a>
 			to a limited number of <a>typographic character units</a>.
 			(It must not truncate only part of a <a>typographic character unit</a>.)
--->
 	</dl>
 
 	<div class="example">