modify docs bugs

Signed-off-by: Nzhongjianfei <zhongjianfei@huawei.com>

zh-cn/application-dev/application-models/create-serviceability.md

@@ -3,43 +3,43 @@
 
 1. 创建ServiceAbility。
 
-  重写ServiceAbility的生命周期方法，添加其他Ability请求与ServiceAbility交互时的处理方法。
+     重写ServiceAbility的生命周期方法，添加其他Ability请求与ServiceAbility交互时的处理方法。
 
-  ```ts
-  import rpc from "@ohos.rpc"
-  
-  class FirstServiceAbilityStub extends rpc.RemoteObject {
-    constructor(des: any) {
-      if (typeof des === 'string') {
-        super(des)
-      } else {
-        return
-      }
-    }
-  }
-  
-  export default {
-    onStart() {
-      console.info('ServiceAbility onStart')
-    },
-    onStop() {
-      console.info('ServiceAbility onStop')
-    },
-    onCommand(want, startId) {
-      console.info('ServiceAbility onCommand')
-    },
-    onConnect(want) {
-      console.info('ServiceAbility onConnect' + want)
-      return new FirstServiceAbilityStub('test')
-    },
-    onDisconnect(want) {
-      console.info('ServiceAbility onDisconnect' + want)
-    }
-  }
-  ```
+   ```ts
+     import rpc from "@ohos.rpc"
+     
+     class FirstServiceAbilityStub extends rpc.RemoteObject {
+       constructor(des: any) {
+         if (typeof des === 'string') {
+           super(des)
+         } else {
+           return
+         }
+       }
+     }
+     
+     export default {
+       onStart() {
+         console.info('ServiceAbility onStart')
+       },
+       onStop() {
+         console.info('ServiceAbility onStop')
+       },
+       onCommand(want, startId) {
+         console.info('ServiceAbility onCommand')
+       },
+       onConnect(want) {
+         console.info('ServiceAbility onConnect' + want)
+         return new FirstServiceAbilityStub('test')
+       },
+       onDisconnect(want) {
+         console.info('ServiceAbility onDisconnect' + want)
+       }
+     }
+   ```
 
 2. 注册ServiceAbility。
-    
+   
     ServiceAbility需要在应用配置文件config.json中进行注册，注册类型type需要设置为service。"visible"属性表示ServiceAbility是否可以被其他应用调用，true表示可以被其他应用调用，false表示不能被其他应用调用（仅应用内可以调用）。若ServiceAbility需要被其他应用调用，注册ServiceAbility时需要设置"visible"为true，同时需要设置支持关联启动。ServiceAbility的启动规则详见[组件启动规则](component-startup-rules.md)章节。
     
     ```json