Doc: Update RectAreaLight.html (mrdoob#23469)

* Update RectAreaLight.html

* Update RectAreaLight.html

Author: puxiao

docs/api/en/lights/RectAreaLight.html

@@ -34,7 +34,7 @@ <h2>Code Example</h2>
 rectLight.lookAt( 0, 0, 0 );
 scene.add( rectLight )
 
-const rectLightHelper = new THREE.RectAreaLightHelper( rectLight );
+const rectLightHelper = new RectAreaLightHelper( rectLight );
 rectLight.add( rectLightHelper );
 		</code>
 

docs/api/zh/lights/RectAreaLight.html

@@ -33,7 +33,7 @@ <h2>代码示例</h2>
 		rectLight.lookAt( 0, 0, 0 );
 		scene.add( rectLight )
 
-		rectLightHelper = new THREE.RectAreaLightHelper( rectLight );
+		rectLightHelper = new RectAreaLightHelper( rectLight );
 		scene.add( rectLightHelper );
 		</code>