fixed 7d528bb9 from https://gitee.com/ge-yafang/docs/pulls/5669

update zh-cn/application-dev/windowmanager/screenshot-guidelines.md.
Signed-off-by: N@ge-yafang <geyafang@huawei.com>

zh-cn/application-dev/windowmanager/screenshot-guidelines.md

-# 屏幕截图开发概述
+# 屏幕截图开发指导
 
 ## 场景介绍