fix: directoryTree support switcherIcon #1743

Author: tangjinzhou

components/tree/DirectoryTree.jsx

@@ -7,7 +7,12 @@ import Tree, { TreeProps } from './Tree';
 import { calcRangeKeys, getFullKeyList } from './util';
 import Icon from '../icon';
 import BaseMixin from '../_util/BaseMixin';
-import { initDefaultProps, getOptionProps, getListeners } from '../_util/props-util';
+import {
+  initDefaultProps,
+  getOptionProps,
+  getListeners,
+  getComponentFromProp,
+} from '../_util/props-util';
 import { ConfigConsumerProps } from '../config-provider';
 
 // export type ExpandAction = false | 'click' | 'dblclick'; export interface
@@ -195,6 +200,7 @@ export default {
         prefixCls,
         expandedKeys,
         selectedKeys,
+        switcherIcon: getComponentFromProp(this, 'switcherIcon'),
       },
       ref: 'tree',
       class: `${prefixCls}-directory`,