Merge pull request #177 from Sunrisepeak/md_format

docs: fix Q0-A format issue

Author: chyyuu

QA.md

@@ -4,9 +4,9 @@
 
 ### A：
 
-     - [B 站的 GitHub Classroom 视频介绍](https://www.bilibili.com/video/BV12L41147r7?spm_id_from=333.337.search-card.all.click&vd_source=8e19ee6e49f598fda8c17e306d8b3726)
-     - [Youtube 的 GitHub Classroom 视频介绍](https://www.youtube.com/playlist?list=PLIRjfNq867bewk3ZGV6Z7a16YDNRCpK3u)
-     - [GitHub 文档：使用 GitHub Classroom 教学](https://docs.github.com/cn/education/manage-coursework-with-github-classroom/get-started-with-github-classroom)
+- [B 站的 GitHub Classroom 视频介绍](https://www.bilibili.com/video/BV12L41147r7?spm_id_from=333.337.search-card.all.click&vd_source=8e19ee6e49f598fda8c17e306d8b3726)
+- [Youtube 的 GitHub Classroom 视频介绍](https://www.youtube.com/playlist?list=PLIRjfNq867bewk3ZGV6Z7a16YDNRCpK3u)
+- [GitHub 文档：使用 GitHub Classroom 教学](https://docs.github.com/cn/education/manage-coursework-with-github-classroom/get-started-with-github-classroom)
 
 ## Q1：已经在 classroom 中建立了自己的仓库（例如“LearningOS/lab0-0-setup-env-run-os1-chyyuu2022”），但是源仓库“LearningOS/rust-based-os-comp2022”更新了，如何处理？