docs: change slot to # (#5858)

* docs(SwipeCell): change "slot" to "v-slot"

* docs(SwipeCell): change `v-slot` to`#`

* docs(cell): change `slot` to `#`

* docs(checkbox): change `slot` to `v-slot`

* docs(field): change `slot` to `v-slot`

* docs(checkbox): remove wrong comment

* docs(radio): change `slot` to `#`

* docs(search): change `slot` to `#`

* docs(slider): change `slot` to `#`

* docs(switch): change `slot` to `#`

* docs(PullRefresh): change `slot` to `#`

* docs(collapse): change `slot` to `#`

* docs(panel): change `slot` to `#`

* docs(swipe): change `slot` to `#`

* docs(navbar): change `slot` to `#`

* docs(tab): change `slot` to `#`

* docs(tabber): change `slot` to `#`

* docs(TreeSelect): change `slot` to `#`

* docs(card): change `slot` to `#`

* docs(submitBar): change `slot` to `#`

* docs(sku): change `slot` to `#` unsure

* docs(cell): delete waste blank line

* docs(panel): fix indentation

* docs(PullRefresh): change "count" to "Refresh Count"

* docs(radio): delete waste blank line

* docs(search): move props above the event

* docs(submitBar): delete waste `<span>`

* docs(swipCell): delete waste blank line

* docs(tabbar): merge `<img>` into one line

src/tab/README.md

@@ -142,10 +142,10 @@ Use title slot to custom tab title
 
 ```html
 <van-tabs v-model="active">
-  <van-tab v-for="index in 2">
-    <div slot="title">
+  <van-tab v-for="index in 2" :key="index">
+    <template #title>
       <van-icon name="more-o" />tab
-    </div>
+    </template>
     content {{ index }}
   </van-tab>
 </van-tabs>

src/tab/README.zh-CN.md

@@ -146,10 +146,10 @@ export default {
 
 ```html
 <van-tabs v-model="active">
-  <van-tab v-for="index in 2">
-    <div slot="title">
+  <van-tab v-for="index in 2" :key="index">
+    <template #title>
       <van-icon name="more-o" />选项
-    </div>
+    </template>
     内容 {{ index }}
   </van-tab>
 </van-tabs>