[css2] addressed issue 176, minor rewording

--HG--
extra : convert_revision : svn%3A73dc7c4b-06e6-40f3-b4f7-9ed1dbc14bfc/trunk%402515

Author: howcom

css2/generate.src

@@ -511,7 +511,7 @@ specified.
 H1 { counter-reset: section 2 section }
 </pre>
 
-<p>The following example will increment the 'chapter' counter with 3:
+<p>The following example will increment the 'chapter' counter by 3:
 
 <pre>
 H1 { counter-increment: chapter chapter 2 }