!11198 更改浮层示例挑单到3.1release

Merge pull request !11198 from 田雨/OpenHarmony-3.1-Release

zh-cn/application-dev/reference/arkui-ts/ts-universal-attributes-overlay.md

@@ -29,7 +29,7 @@ struct OverlayExample {
             .width(240).height(240)
             .overlay("Winter is a beautiful season, especially when it snows.", {
               align: Alignment.Bottom,
-              offset: { x: 70, y: 100 }
+              offset: { x: 0, y: -15 }
             })
         }.border({ color: Color.Black, width: 2 })
       }.width('100%')