remove unnecessary parens

Author: astearns

css-shapes-1/Overview.bs

@@ -757,7 +757,7 @@ Shapes from Box Values</h2>
 	If the ratio of <code>border-radius/margin</code> is less than 1,
 	and margin is positive, 
 	then the margin box corner radius is
-	<code>border-radius + (margin * (1 + (ratio-1)^3))</code>.
+	<code>border-radius + margin * (1 + (ratio-1)^3)</code>.
 
 	The <dfn value for="<shape-box>, shape-outside">border-box</dfn> value defines the shape
 	enclosed by the outside border edge.
@@ -1116,6 +1116,7 @@ Since <a href="https://www.w3.org/TR/2014/CR-css-shapes-1-20140320/">March 20th
 		<li>Moved path() back from level 2</li>
 		<li>Added handling of negative margins for margin-box</li>
 		<li>Added clarifications to shape-margin examples</li>
+		<li>Added margin=0 case for margin-box shape</li>
 	</ul>
 
 <h3 class="no-num" id="20140211">