Method scrollTop

packages/fairygui/src/scroll/ScrollPane.ts:329–331

* Scroll to top * 滚动到顶部

(bAnimate?: boolean)

     * 滚动到顶部
     */
    public scrollTop(bAnimate?: boolean): void {
        this.setPercY(0, bAnimate ?? false);
    }

    /**
     * Scroll to bottom