Removed unnecessary THREE. from example code.

docs/manual/en/introduction/Loading-3D-models.html

@@ -95,7 +95,7 @@
 	</p>
 
 	<code>
-		var loader = new THREE.GLTFLoader();
+		var loader = new GLTFLoader();
 
 		loader.load( 'path/to/model.glb', function ( gltf ) {