IssueNo: #I7XVG3:[新需求]: Rectify the arkts syntax 3

Description: Rectify the arkts syntax in arkts-extend.md.
Sig: SIG_ApplicaitonFramework
Feature or Bugfix: Feature
Binary Source: No
Signed-off-by: N189******51 <lipeicheng5@huawei.com>

zh-cn/application-dev/quick-start/arkts-extend.md

@@ -64,27 +64,27 @@
 - \@Extend装饰的方法的参数可以为function，作为Event事件的句柄。
 
   ```ts
-@Extend(Text) function makeMeClick(onClick: () => void) {
-  .backgroundColor(Color.Blue)
-  .onClick(onClick)
-}
+  @Extend(Text) function makeMeClick(onClick: () => void) {
+    .backgroundColor(Color.Blue)
+    .onClick(onClick)
+  }
 
-@Entry
-@Component
-struct FancyUse {
-  @State label: string = 'Hello World';
+  @Entry
+  @Component
+  struct FancyUse {
+    @State label: string = 'Hello World';
 
-  onClickHandler() {
-    this.label = 'Hello ArkUI';
-  }
+    onClickHandler() {
+      this.label = 'Hello ArkUI';
+    }
 
-  build() {
-    Row({ space: 10 }) {
-      Text(`${this.label}`)
-        .makeMeClick(this.onClickHandler)
+    build() {
+      Row({ space: 10 }) {
+        Text(`${this.label}`)
+          .makeMeClick(this.onClickHandler)
+      }
     }
   }
-}
   ```
 
 - \@Extend的参数可以为[状态变量](arkts-state-management-overview.md)，当状态变量改变时，UI可以正常的被刷新渲染。