update docs

Signed-off-by: NAnnie_wang <annie.wangli@huawei.com>

en/application-dev/database/database-relational-guidelines.md

@@ -140,7 +140,7 @@ You can obtain the distributed table name for a remote device based on the local
 
 | Class    | API                                                      | Description                                                        |
 | -------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
-| RdbStore | sync(mode: SyncMode, predicates: RdbPredicates): Promise\<Array\<[string, number]>> | Synchronizes data between devices. This API uses a promise to return the result.<br>- **mode**: synchronization mode.  **SYNC_MODE_PUSH** means to push data from the local device to a remote device. **SYNC_MODE_PULL** means to pull data from a remote device to the local device.<br>- **predicates**: specifies the data and devices to synchronize.<br>- **string**: device ID. <br>- **number**: synchronization status of that device. The value **0** indicates a successful synchronization. Other values indicate a synchronization failure.|
+| RdbStore | sync(mode: SyncMode, predicates: RdbPredicates): Promise\<Array\<[string, number]>> | Synchronizes data between devices. This API uses a promise to return the result.<br>- **mode**: synchronization mode.  **SYNC_MODE_PUSH** means to push data from the local device to a remote device. **SYNC_MODE_PULL** means to pull data from a remote device to the local device.<br>- **predicates**: specifies the data and devices to synchronize.<br>- **string**: device ID. <br>- **number**: synchronization status of each device. The value **0** indicates a successful synchronization. Other values indicate a synchronization failure.|
 
 **Registering an RDB Store Observer**