fix PerspectiveCamera docs

src/cameras/PerspectiveCamera.js

@@ -130,17 +130,17 @@ PerspectiveCamera.prototype = Object.assign( Object.create( Camera.prototype ),
 	 *   var fullHeight = h * 2;
 	 *
 	 *   --A--
-	 *   camera.setOffset( fullWidth, fullHeight, w * 0, h * 0, w, h );
+	 *   camera.setViewOffset( fullWidth, fullHeight, w * 0, h * 0, w, h );
 	 *   --B--
-	 *   camera.setOffset( fullWidth, fullHeight, w * 1, h * 0, w, h );
+	 *   camera.setViewOffset( fullWidth, fullHeight, w * 1, h * 0, w, h );
 	 *   --C--
-	 *   camera.setOffset( fullWidth, fullHeight, w * 2, h * 0, w, h );
+	 *   camera.setViewOffset( fullWidth, fullHeight, w * 2, h * 0, w, h );
 	 *   --D--
-	 *   camera.setOffset( fullWidth, fullHeight, w * 0, h * 1, w, h );
+	 *   camera.setViewOffset( fullWidth, fullHeight, w * 0, h * 1, w, h );
 	 *   --E--
-	 *   camera.setOffset( fullWidth, fullHeight, w * 1, h * 1, w, h );
+	 *   camera.setViewOffset( fullWidth, fullHeight, w * 1, h * 1, w, h );
 	 *   --F--
-	 *   camera.setOffset( fullWidth, fullHeight, w * 2, h * 1, w, h );
+	 *   camera.setViewOffset( fullWidth, fullHeight, w * 2, h * 1, w, h );
 	 *
 	 *   Note there is no reason monitors have to be the same size or in a grid.
 	 */