fixed e59f5aaf from https://gitee.com/HelloCrease/docs/pulls/16147

update zh-cn/application-dev/reference/arkui-ts/ts-universal-attributes-text-style.md.
Signed-off-by: NLiAn <lian15@huawei.com>
Signed-off-by: NLiAn <lian15@huawei.com>

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

@@ -58,4 +58,4 @@ struct TextStyleExample {
 }
 ```
 
-![textstyle](figures/textstyle.PNG)
+![textstyle](figures/textstyle.png)