update notification docs

Signed-off-by: Nester.zhou <ester.zhou@huawei.com>

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

 # Emitter
 
-> **NOTE**<br>
+The **Emitter** module provides APIs for sending and processing in-process events, including the APIs for processing events that are subscribed to in persistent or one-shot manner, unsubscribing from events, and emitting events to the event queue.
+
+> **NOTE**
+>
 > The initial APIs of this module are supported since API version 7.
 
 ## Modules to Import
@@ -17,12 +20,14 @@ None
 
 Enumerates the event emit priority levels.
 
- | Name | Value | Description |
- | --------- | ---- | ------------------------------------------------- |
- | IMMEDIATE | 0 | The event will be emitted immediately.<br>**System capability**: SystemCapability.Notification.Emitter |
- | HIGH | 1 | The event will be emitted before low-priority events.<br>**System capability**: SystemCapability.Notification.Emitter |
- | LOW | 2 | The event will be emitted before idle-priority events. By default, an event is in LOW priority.<br>**System capability**: SystemCapability.Notification.Emitter |
- | IDLE | 3 | The event will be emitted after all the other events.<br>**System capability**: SystemCapability.Notification.Emitter |
+**System capability**: SystemCapability.Notification.Emitter
+
+| Name     | Value  | Description                                             |
+| --------- | ---- | ------------------------------------------------- |
+| IMMEDIATE | 0    | The event will be emitted immediately.                               |
+| HIGH      | 1    | The event will be emitted before low-priority events.                        |
+| LOW       | 2    | The event will be emitted before idle-priority events. By default, an event is in LOW priority.  |
+| IDLE      | 3    | The event will be emitted after all the other events.           |
 
 ## emitter.on
 
@@ -34,10 +39,10 @@ Subscribes to an event in persistent manner. This API uses a callback to return
 
 **Parameters**
 
- | Name | Type | Mandatory | Description |
- | -------- | ----------------------------------- | ---- | ------------------------ |
- | event | [InnerEvent](#innerevent) | Yes | Event to subscribe to in persistent manner. |
- | callback | Callback\<[EventData](#eventdata)\> | Yes | Callback used to return the event. |
+| Name  | Type                               | Mandatory| Description                    |
+| -------- | ----------------------------------- | ---- | ------------------------ |
+| event    | [InnerEvent](#innerevent)           | Yes  | Event to subscribe to in persistent manner.          |
+| callback | Callback\<[EventData](#eventdata)\> | Yes  | Callback used to return the event.|
 
 **Example**
 
@@ -61,10 +66,10 @@ Subscribes to an event in one-shot manner and unsubscribes from it after the eve
 
 **Parameters**
 
- | Name | Type | Mandatory | Description |
- | -------- | ----------------------------------- | ---- | ------------------------ |
- | event | [InnerEvent](#innerevent) | Yes | Event to subscribe to in one-shot manner. |
- | callback | Callback\<[EventData](#eventdata)\> | Yes | Callback used to return the event. |
+| Name  | Type                               | Mandatory| Description                    |
+| -------- | ----------------------------------- | ---- | ------------------------ |
+| event    | [InnerEvent](#innerevent)           | Yes  | Event to subscribe to in one-shot manner.          |
+| callback | Callback\<[EventData](#eventdata)\> | Yes  | Callback used to return the event.|
 
 **Example**
 
@@ -88,9 +93,9 @@ Unsubscribes from an event.
 
 **Parameters**
 
- | Name | Type | Mandatory | Description |
- | ------- | ------ | ---- | ------ |
- | eventId | number | Yes | Event ID. |
+| Name | Type  | Mandatory| Description  |
+| ------- | ------ | ---- | ------ |
+| eventId | number | Yes  | Event ID.|
 
 **Example**
 
@@ -108,10 +113,10 @@ Emits an event to the event queue.
 
 **Parameters**
 
- | Name | Type | Mandatory | Description |
- | ------ | ------------------------- | ---- | -------------- |
- | event | [InnerEvent](#innerevent) | Yes | Event to emit. |
- | data | [EventData](#eventdata) | No | Data carried by the event. |
+| Name| Type                     | Mandatory| Description          |
+| ------ | ------------------------- | ---- | -------------- |
+| event  | [InnerEvent](#innerevent) | Yes  | Event to emit.    |
+| data   | [EventData](#eventdata)   | No  | Data carried by the event.|
 
 **Example**
 
@@ -130,17 +135,21 @@ emitter.emit(innerEvent, eventData);
 
 ## InnerEvent
 
-Describes an intra-process event.
+Describes an in-process event.
 
- | Name | Type | Readable | Writable | Description |
- | -------- | ------------------------------- | ---- | ---- | ---------------------------------- |
- | eventId | number | Yes | Yes | Event ID, which is used to identify an event.<br>**System capability**: SystemCapability.Notification.Emitter |
- | priority | [EventPriority](#eventpriority) | Yes | Yes | Emit priority of the event.<br>**System capability**: SystemCapability.Notification.Emitter |
+**System capability**: SystemCapability.Notification.Emitter
+
+| Name    | Type                       | Readable| Writable| Description                              |
+| -------- | ------------------------------- | ---- | ---- | ---------------------------------- |
+| eventId  | number                          | Yes  | Yes  | Event ID, which is used to identify an event.|
+| priority | [EventPriority](#eventpriority) | Yes  | Yes  | Emit priority of the event.        |
 
 ## EventData
 
 Describes the data passed in the event.
 
- | Name | Type | Readable | Writable | Description |
- | ---- | ------------------ | ---- | ---- | -------------- |
- | data | [key: string]: any | Yes | Yes | Data carried by the event. The data type can be String, Integer, or Boolean.<br>**System capability**: SystemCapability.Notification.Emitter |
+**System capability**: SystemCapability.Notification.Emitter
+
+| Name| Type          | Readable| Writable| Description          |
+| ---- | ------------------ | ---- | ---- | -------------- |
+| data | [key: string]: any | Yes  | Yes  | Data carried by the event. The data type can be String, Integer, or Boolean.|