doc(TreeSelect): update fieldNames docs (#6623)

Author: CCherry07

components/tree-select/index.en-US.md

@@ -23,7 +23,7 @@ Tree selection control.
 | dropdownClassName | className of dropdown menu | string | - |  |  |
 | dropdownMatchSelectWidth | Determine whether the dropdown menu and the select input are the same width. Default set `min-width` same as input. Will ignore when value less than select width. `false` will disable virtual scroll | boolean \| number | true |  |  |
 | dropdownStyle | To set the style of the dropdown menu | object | - |  |  |
-| fieldNames | Replace the label,value, key and children fields in treeNode with the corresponding fields in treeData | object | {children:'children', label:'title', key:'key', value: 'value' } |  | 3.0.0 |
+| fieldNames | Replace the label,value and children fields in treeNode with the corresponding fields in treeData | object | { children:'children', label:'title', value:'value' } |  | 3.0.0 |
 | filterTreeNode | Whether to filter treeNodes by input value. The value of `treeNodeFilterProp` is used for filtering by default. | boolean\|Function(inputValue: string, treeNode: TreeNode) (should return boolean) | Function |  |  |
 | getPopupContainer | To set the container of the dropdown menu. The default is to create a `div` element in `body`, you can reset it to the scrolling area and make a relative reposition. | Function(triggerNode) | () => document.body |  |  |
 | labelInValue | whether to embed label in value, turn the format of value from `string` to `{value: string, label: VNode, halfChecked: string[]}` | boolean | false |  |  |

components/tree-select/index.zh-CN.md

@@ -24,7 +24,7 @@ cover: https://gw.alipayobjects.com/zos/alicdn/Ax4DA0njr/TreeSelect.svg
 | dropdownClassName | 下拉菜单的 className 属性 | string | - |  |  |
 | dropdownMatchSelectWidth | 下拉菜单和选择器同宽。默认将设置 `min-width`，当值小于选择框宽度时会被忽略。false 时会关闭虚拟滚动 | boolean \| number | true |  |  |
 | dropdownStyle | 下拉菜单的样式 | object | - |  |  |
-| fieldNames | 替换 treeNode 中 label,value,key,children 字段为 treeData 中对应的字段 | object | {children:'children', label:'title', value: 'value' } |  | 3.0.0 |
+| fieldNames | 替换 treeNode 中 label,value,children 字段为 treeData 中对应的字段 | object | {children:'children', label:'title', value: 'value' } |  | 3.0.0 |
 | filterTreeNode | 是否根据输入项进行筛选，默认用 treeNodeFilterProp 的值作为要筛选的 TreeNode 的属性值 | boolean\|Function(inputValue: string, treeNode: TreeNode) (函数需要返回 bool 值) | Function |  |  |
 | getPopupContainer | 菜单渲染父节点。默认渲染到 body 上，如果你遇到菜单滚动定位问题，试试修改为滚动的区域，并相对其定位。 | Function(triggerNode) | () => document.body |  |  |
 | labelInValue | 是否把每个选项的 label 包装到 value 中，会把 value 类型从 `string` 变为 `{value: string, label: VNode, halfChecked(treeCheckStrictly 时有效): string[] }` 的格式 | boolean | false |  |  |