[mediaqueries] Fix typo in example

Author: frivoal

mediaqueries/Overview.bs

@@ -985,7 +985,7 @@ Width: the 'width' feature</h3>
 		(the part of the screen/paper where the document is rendered)
 		widths between 400 and 700 pixels:
 
-		<pre>@media (400px <= min-width <= 700px) { … }</pre>
+		<pre>@media (400px <= width <= 700px) { … }</pre>
 	</div>
 
 	<div class="example">