[Doc] Demo: use v-slot shorthand (#3574)

packages/collapse/demo/index.vue

@@ -27,8 +27,8 @@
     <demo-block :title="$t('titleSlot')">
       <van-collapse v-model="active3">
         <van-collapse-item>
-          <template v-slot:title>
-            <div>{{ $t('title') + 1 }}<van-icon name="question-o" /></div>
+          <template #title>
+            {{ $t('title') + 1 }}<van-icon name="question-o" />
           </template>
           {{ $t('text') }}
         </van-collapse-item>

packages/collapse/test/__snapshots__/demo.spec.js.snap

@@ -57,9 +57,8 @@ exports[`renders demo correctly 1`] = `
       <div class="van-collapse-item">
         <div role="button" tabindex="0" aria-expanded="false" class="van-cell van-cell--clickable van-collapse-item__title">
           <div class="van-cell__title">
-            <div>标题1<i class="van-icon van-icon-question-o">
-                <!----></i></div>
-          </div><i class="van-icon van-icon-arrow van-cell__right-icon">
+            标题1<i class="van-icon van-icon-question-o">
+              <!----></i></div><i class="van-icon van-icon-arrow van-cell__right-icon">
             <!----></i>
         </div>
       </div>