docs(DatetimePicker): update demo (#6215)

* docs(DatetimePicker): update demo

* chore: revert

* test: update snapshot

src/area/README.md

@@ -20,7 +20,7 @@ Vue.use(Area);
 To initailize `Area` component, `area-list` property is required. Data structure will be introduced later.
 
 ```html
-<van-area :area-list="areaList" />
+<van-area title="Title" :area-list="areaList" />
 ```
 
 ### Initial Value
@@ -28,7 +28,7 @@ To initailize `Area` component, `area-list` property is required. Data structure
 To have a selected value，simply pass the `code` of target area to `value` property.
 
 ```html
-<van-area :area-list="areaList" value="110101" />
+<van-area title="Title" :area-list="areaList" value="110101" />
 ```
 
 ### Columns Number
@@ -36,7 +36,7 @@ To have a selected value，simply pass the `code` of target area to `value` prop
 `columns-num` property is used to config number of columns to be displayed. This component has 3 columns corresponding to a 3 level picker by default. Set `columns-num` with 2, you'll have a 2 level picker.
 
 ```html
-<van-area :area-list="areaList" :columns-num="2" title="Title" />
+<van-area title="Title" :area-list="areaList" :columns-num="2" />
 ```
 
 ### Columns Placeholder
@@ -45,9 +45,9 @@ To have a selected value，simply pass the `code` of target area to `value` prop
 
 ```html
 <van-area
+  title="Title"
   :area-list="areaList"
   :columns-placeholder="['Choose', 'Choose', 'Choose']"
-  title="Title"
 />
 ```