docs: should hide some demes in vant-weapp

src/tab/demo/index.vue

@@ -67,7 +67,7 @@
       </van-tabs>
     </demo-block>
 
-    <demo-block v-if="!$attrs.weapp" :title="$t('title7')">
+    <demo-block v-if="!isWeapp" :title="$t('title7')">
       <van-tabs :active="active">
         <van-tab v-for="index in 2" :key="index">
           <template #title>
@@ -94,7 +94,7 @@
       </van-tabs>
     </demo-block>
 
-    <demo-block v-if="!$attrs.weapp" :title="$t('title10')">
+    <demo-block v-if="!isWeapp" :title="$t('title10')">
       <van-tabs scrollspy sticky>
         <van-tab :title="$t('tab') + index" v-for="index in 10" :key="index">
           {{ $t('content') }} {{ index }}