cascader 组件，自定义 fieldNames 时，搜索展示 bug

[gauseen]

• I have searched the issues of this repository and believe that this is not a duplicate.

Version

1.3.10

Environment

window 10, chrome 75.0.3770.142, vue 2.5.17

Reproduction link

Steps to reproduce

重现请看 https://codesandbox.io/embed/vue-antd-template-9q80s

What is expected?

搜索时，展示 Zhejiang/Hangzhou/West Lake，由 / 分割开展示

What is actually happening?

搜索时，展示 ZhejiangHangzhouWest Lake，没有用 / 分割开展示

[tangjinzhou]

fieldNames 定义 lable 和 value 时 暂不可使用同一值

[github-actions]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 7 days

[github-actions]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.