update zh-cn/application-dev/reference/arkui-ts/ts-components-canvas-canvasgradient.md.

Signed-off-by: qiqimao<qiqimao1234@163.com>
Signed-off-by: Nqiqimao <qiqimao1234@163.com>

zh-cn/application-dev/reference/arkui-ts/ts-components-canvas-canvasgradient.md

@@ -46,6 +46,9 @@ addColorStop(offset: number, color: string): void
       .width('100%')
       .height('100%')
     }}
+```
+
+
 
 
 ![zh-cn_image_0000001194032516](figures/zh-cn_image_0000001194032516.png)