Add doc (16924)

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

en/release-notes/changelogs/OpenHarmony_4.0.5.5/changelogs-arkui.md

+# ArkUI Subsystem Changelog
+
+## cl.arkui.1 Change in the Default Scrollbar State of \<List> and \<Gird> Components
+
+Changed the default state of the scrollbar in the **\<List>** and **\<Gird>** components from **BarState.Off** to **BarState.Auto**.
+
+**Change Impact**
+
+In the scenario where the scrollbar status is not set in the **\<List>** and **\<Gird>** components:
+
+- Before change:
+
+  The scrollbar is not displayed.
+
+- After change:
+
+  The scrollbar is displayed during scrolling and is hidden 2 seconds after the scrolling stops.
+
+**Key API/Component Changes**
+
+**scrollBar** attribute of the **\<List>** and **\<Gird>** components:
+- [List](../../../application-dev/reference/arkui-ts/ts-container-list.md#attributes)
+- [Grid](../../../application-dev/reference/arkui-ts/ts-container-grid.md#attributes)
+
+**Adaptation Guide**
+
+In scenarios where the scrollbar is not required, set the **scrollBar** attribute of the **\<List>** and **\<Gird>** components to **BarState.Off**.
+
+The code snippet is as follows:
+```ts
+// xxx.ets
+@Entry
+@Component
+struct ListItemExample {
+  private arr: number[] = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+  build() {
+    Column() {
+      List({ space: 20, initialIndex: 0 }) {
+        ForEach(this.arr, (item) => {
+          ListItem() {
+            Text('' + item)
+              .width('100%').height(100).fontSize(16)
+              .textAlign(TextAlign.Center).borderRadius(10).backgroundColor(0xFFFFFF)
+          }
+        }, item => item)
+      }
+      .width('90%')
+      .scrollBar(BarState.Off)
+    }.width('100%').height('100%').backgroundColor(0xDCDCDC).padding({ top: 5 })
+  }
+}
+```