[Bug Report] 多语言里繁体翻译不全

### Element UI version
2.15.14

### OS/Browsers version
mac/chrome

### Vue version
2.7.16

### Reproduction Link
https://github.com/ElemeFE/element/blob/dev/src/locale/lang/zh-TW.js

### Steps to reproduce
源码的一些地方待完善, 以下是源码的部分
...
transfer: {
noMatch: '無匹配資料',
noData: '無資料',
titles: ['List 1', 'List 2'], // to be translated
filterPlaceholder: 'Enter keyword', // to be translated
noCheckedFormat: '{total} items', // to be translated
hasCheckedFormat: '{checked}/{total} checked' // to be translated
},
image: {
error: '加載失敗'
},
pageHeader: {
title: '返回'
},
popconfirm: {
confirmButtonText: 'Yes', // to be translated
cancelButtonText: 'No' // to be translated
},

### What is Expected?
期待完整的支持繁体字国际化

### What is actually happening?
部分繁体字国际化不完整