调整threejs类型

src/PlaneExt.ts

@@ -1,9 +1,9 @@
 import * as THREE from 'three';
-import { Vector3, Line3 } from "three";
+import { Vector3, Line3, Plane } from "three";
 
-export class PlaneExt extends THREE.Plane
+export class PlaneExt extends Plane
 {
-    constructor(normal?: THREE.Vector3, constant?: number)
+    constructor(normal?: Vector3, constant?: number)
     {
         super(normal, constant);
     }