update docs

Signed-off-by: Nge-yafang <geyafang@huawei.com>

en/application-dev/device/usb-guidelines.md

@@ -35,63 +35,63 @@ You can set a USB device as the USB host to connect to other USB devices for dat
 1.  Obtain the USB device list.
 
     ```js
-    // Import the USB API package.
-    import usb from '@ohos.usbV9';
-    // Obtain the USB device list.
-    let deviceList = usb.getDevices();
-    /*
-    Example deviceList structure
-    [
-      {
-        name: "1-1",
-        serial: "",
-        manufacturerName: "",
-        productName: "",
-        version: "",
-        vendorId: 7531,
-        productId: 2,
-        clazz: 9,
-        subclass: 0,
-        protocol: 1,
-        devAddress: 1,
-        busNum: 1,
-        configs: [
+        // Import the USB API package.
+        import usb from '@ohos.usbV9';
+        // Obtain the USB device list.
+        let deviceList = usb.getDevices();
+        /*
+        Example deviceList structure
+        [
           {
-            id: 1,
-            attributes: 224,
-            isRemoteWakeup: true,
-            isSelfPowered: true,
-            maxPower: 0,
             name: "1-1",
-            interfaces: [
+            serial: "",
+            manufacturerName: "",
+            productName: "",
+            version: "",
+            vendorId: 7531,
+            productId: 2,
+            clazz: 9,
+            subclass: 0,
+            protocol: 1,
+            devAddress: 1,
+            busNum: 1,
+            configs: [
               {
-                id: 0,
-                protocol: 0,
-                clazz: 9,
-                subclass: 0,
-                alternateSetting: 0,
+                id: 1,
+                attributes: 224,
+                isRemoteWakeup: true,
+                isSelfPowered: true,
+                maxPower: 0,
                 name: "1-1",
-                endpoints: [
+                interfaces: [
                   {
-                    address: 129,
-                    attributes: 3,
-                    interval: 12,
-                    maxPacketSize: 4,
-                    direction: 128,
-                    number: 1,
-                    type: 3,
-                    interfaceId: 0,
+                    id: 0,
+                    protocol: 0,
+                    clazz: 9,
+                    subclass: 0,
+                    alternateSetting: 0,
+                    name: "1-1",
+                    endpoints: [
+                      {
+                        address: 129,
+                        attributes: 3,
+                        interval: 12,
+                        maxPacketSize: 4,
+                        direction: 128,
+                        number: 1,
+                        type: 3,
+                        interfaceId: 0,
+                     }
+                   ]
                  }
                ]
              }
            ]
          }
        ]
-     }
-   ]
-   */
-
-   ```
+    */
+    ```
+   
 
 2.  Obtain the device operation permissions.