update api and user guide

Signed-off-by: Nrcy-hw <renchunyang@huawei.com>

en/application-dev/reference/apis/js-apis-reminderAgent.md

@@ -30,7 +30,7 @@ Publishes an agent-powered reminder. This API uses an asynchronous callback to r
 
 **Example**
   ```
-  let timer : reminderAgent.ReminderRequestTimer = {
+  timer: {
       reminderType: reminderAgent.ReminderType.REMINDER_TYPE_TIMER,
       triggerTimeInSeconds: 10
   }
@@ -60,7 +60,7 @@ Publishes an agent-powered reminder. This API uses a promise callback to return
 
 **Example**
   ```
-  let timer : reminderAgent.ReminderRequestTimer = {
+  timer: {
       reminderType: reminderAgent.ReminderType.REMINDER_TYPE_TIMER,
       triggerTimeInSeconds: 10
   }

zh-cn/application-dev/reference/apis/js-apis-reminderAgent.md

@@ -30,7 +30,7 @@ publishReminder(reminderReq: ReminderRequest, callback: AsyncCallback<number&
 
 **示例**：
 ```
-  let timer : reminderAgent.ReminderRequestTimer = {
+  timer: {
       reminderType: reminderAgent.ReminderType.REMINDER_TYPE_TIMER,
       triggerTimeInSeconds: 10
   }
@@ -60,7 +60,7 @@ publishReminder(reminderReq: ReminderRequest): Promise<number>
 
 **示例**：
 ```
-  let timer : reminderAgent.ReminderRequestTimer = {
+  timer: {
       reminderType: reminderAgent.ReminderType.REMINDER_TYPE_TIMER,
       triggerTimeInSeconds: 10
   }