[Doc] translate theme & demo pages (#320)

* fix: Tabbar icon line-height

* [new feature] progress add showPivot prop

* [new feature] TabItem support vue-router

* [new feature] update document header style

* [Doc] add toast english ducoment

* [bugfix] Search box-sizing wrong

* [Doc] update vant-demo respo

* [Doc] translate theme & demo pages

docs/markdown/zh-CN/theme.md

@@ -9,7 +9,7 @@
 // 引入基础样式
 import 'vant/packages/vant-css/src/base.css';
 
-// 引入组价对应的样式
+// 引入组件对应的样式
 import 'vant/packages/vant-css/src/button.css';
 import 'vant/packages/vant-css/src/checkbox.css';
 ```