Tree: update doc (#5968)

* Tree: update doc

* fix doc

examples/docs/en-US/tree.md

@@ -876,8 +876,9 @@ Only one node among the same level can be expanded at one time.
 ### props
 | Attribute | Description                              | Type   | Accepted Values | Default |
 | --------- | ---------------------------------------- | ------ | --------------- | ------- |
-| label     | specify which key of node object is used as the node's label | string | —               | —       |
-| children  | specify which key of node object is used as the node's subtree | string | —               | —       |
+| label     | specify which key of node object is used as the node's label | string, function(data, node) | —               | —       |
+| children | specify which node object is used as the node's subtree | string, function(data, node) | —               | —       |
+| disabled | specify which node's checkbox disabled |  boolean, function(data, node) | —    | —    |
 
 ### Method
 `Tree` has the following method, which returns the currently selected array of nodes.

examples/docs/zh-CN/tree.md

@@ -875,8 +875,9 @@
 ### props
 | 参数       | 说明                | 类型     | 可选值  | 默认值  |
 | -------- | ----------------- | ------ | ---- | ---- |
-| label    | 指定节点标签为节点对象的某个属性值 | string | —    | —    |
-| children | 指定子树为节点对象的某个属性值   | string | —    | —    |
+| label    | 指定节点标签为节点对象的某个属性值 | string, function(data, node) | —    | —    |
+| children | 指定子树为节点对象的某个属性值 | string, function(data, node) | —    | —    |
+| disabled | 指定节点选择框是否禁用 |  boolean, function(data, node) | —    | —    |
 
 ### 方法
 `Tree` 拥有如下方法，返回目前被选中的节点数组：