[css2] Fixed a broken link.

--HG--
extra : convert_revision : svn%3A73dc7c4b-06e6-40f3-b4f7-9ed1dbc14bfc/trunk%402049

Author: bert-github

css2/generate.src

@@ -87,7 +87,7 @@ q:before {
 </div>
 
 <p>In a :before or :after pseudo-element declaration, non-inherited
-properties take their <a href="cascade.html#initial-value">initial
+properties take their <a href="about.html#initial-value">initial
 values</a>.</p>
 
 <div class=example>