modify popup example

Signed-off-by: Nzhaoxinyu <zhaoxinyu20@huawei.com>
Change-Id: I046630756e0e49ce43628ef7331ddd9926a714da

en/application-dev/reference/arkui-ts/ts-universal-attributes-popup.md

@@ -85,7 +85,7 @@ struct PopupExample {
             }
           },
           onStateChange: (e) => {
-            console.info(e.isVisible.toString())
+            console.info(JSON.stringify(e.isVisible))
             if (!e.isVisible) {
               this.handlePopup = false
             }

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

@@ -85,7 +85,7 @@ struct PopupExample {
             }
           },
           onStateChange: (e) => {
-            console.info(e.isVisible.toString())
+            console.info(JSON.stringify(e.isVisible))
             if (!e.isVisible) {
               this.handlePopup = false
             }