update zh-cn/application-dev/reference/arkui-ts/ts-container-column.md.

Signed-off-by: zhongyuyan <zhongyuyan1@huawei.com> 缺少根组件，添加了一个Column

zh-cn/application-dev/reference/arkui-ts/ts-container-column.md

@@ -115,6 +115,7 @@ Column\(value:\{space?: Length\}\)
 @Component
 struct ColumnExample {
   build() {
+    Column() {
         Text('space').fontSize(9).fontColor(0xCCCCCC).width('90%')
         Column({ space: 5 }) {
           Column().width('100%').height(30).backgroundColor(0xAFEEEE)