[Improvement] optimize staticClass (#337)

* 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

* [Doc] add Internationalization document

* [bugfix] remove unnecessary props

* [fix] optimize clickoutside

* [new feature] optimize find-parent

* [new feature]: change document title accordinng to language

* [new feature] Pagination code review

* [improvement] adjust icon-font unicode

* [improvement] Icon spinner color inherit

* [improvement] icon default width

* [bugfix] DateTimePicker validate date props

* [bugfix] Tab item text ellipsis

* [improvement] optimize single line ellipsis

* [Improvement] optimzie staticClass

packages/toast/toast.vue

@@ -1,7 +1,7 @@
 <template>
   <transition name="van-toast-fade">
     <div class="van-toast-wrapper" v-show="visible">
-      <div :class="['van-toast', `van-toast--${displayStyle}`, `van-toast--${position}`]">
+      <div class="van-toast" :class="[`van-toast--${displayStyle}`, `van-toast--${position}`]">
         <!-- text only -->
         <div v-if="displayStyle === 'text'">{{ message }}</div>
         <div v-if="displayStyle === 'html'" v-html="message" />
@@ -13,7 +13,7 @@
           <div v-if="message" class="van-toast__text">{{ message }}</div>
         </template>
       </div>
-      <div :class="['van-toast__overlay', { 'van-toast__overlay--mask': mask }]" v-if="forbidClick || mask" />
+      <div class="van-toast__overlay" :class="{ 'van-toast__overlay--mask': mask }" v-if="forbidClick || mask" />
     </div>
   </transition>
 </template>