Update Frustum.html

docs/api/en/math/Frustum.html

@@ -11,7 +11,7 @@
 
 		<p class="desc">
 			[link:http://en.wikipedia.org/wiki/Frustum Frustums] are used to determine what is
-			inside the camera's field of view. They help speed up the rendering process - object which lie
+			inside the camera's field of view. They help speed up the rendering process - objects which lie
 			outside a camera's frustum can safely be excluded from rendering.<br /><br />
 
 			This class is mainly intended for use internally by a renderer for calculating