Update README.md

README.md

@@ -90,6 +90,7 @@ Adapted to screen height: `ScreenUtil().setHeight(200)`,
 If your dart sdk>=2.6, you can use extension functions:
 
 example:
+
 instead of :
 ```
 Container(
@@ -322,4 +323,4 @@ class _ExampleWidgetState extends State<ExampleWidget> {
 effect:
 
 ![effect](demo_en.png)
-![tablet effect](demo_tablet_en.png)
\ No newline at end of file
+![tablet effect](demo_tablet_en.png)