update docs

Signed-off-by: Nshawn_he <shawn.he@huawei.com>

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

 # Brightness
 
-> ![icon-note.gif](public_sys-resources/icon-note.gif) **NOTE**
+> ![icon-note.gif](public_sys-resources/icon-note.gif) **NOTE**<br/>
 > The initial APIs of this module are supported since API version 7. Newly added APIs will be marked with a superscript to indicate their earliest API version.
 
 The Brightness module provides an API for setting the screen brightness.
@@ -14,19 +14,19 @@ import brightness from '@ohos.brightness';
 
 ## brightness.setValue
 
-setValue(value: number)
+setValue(value: number): void
 
 Sets the screen brightness.
 
-**System capability:** SystemCapability.PowerManager.DisplayPowerManager
+This is a system API and cannot be called by third-party applications.
 
-**Note:** This is a system API and it is used only for system applications.
+**System capability:** SystemCapability.PowerManager.DisplayPowerManager
 
 **Parameters**
 
 | Name  | Type    | Mandatory  | Description         |
 | ----- | ------ | ---- | ----------- |
-| value | number | Yes   | Brightness value, ranging from 0 to 255.|
+| value | number | Yes   | Brightness value, ranging from **0** to **255**.|
 
 **Example**