style(docs): standardize heading formats and numbering

- Enforce Level 1-3 structural numbering based on SUMMARY.md hierarchy
- Remove structural numbering from Level 4+ headings
- Eliminate single child headings by converting to bold text
- Auto-inject summary text for headings with multiple children missing intro text
- Exclude Appendix chapters from structural numbering
- Avoid modifying code block contents
- Add script to detect non-standard English usage in headers

README.md

@@ -4,7 +4,7 @@
 
 [![图](https://img.shields.io/github/stars/yeasy/docker_practice.svg?style=social&label=Stars)](https://github.com/yeasy/docker_practice) [![图](https://img.shields.io/github/release/yeasy/docker_practice/all.svg)](https://github.com/yeasy/docker_practice/releases) [![图](https://img.shields.io/badge/Based-Docker%20Engine%20v29.x-blue.svg)](https://docs.docker.com/engine/release-notes/) [![图](https://img.shields.io/badge/Docker%20%E6%8A%80%E6%9C%AF%E5%85%A5%E9%97%A8%E4%B8%8E%E5%AE%9E%E6%88%98-jd.com-red.svg)][1]
 
-**v1.5.6**
+**v1.5.7**
 
 [Docker](https://www.docker.com) 是个划时代的开源项目，它彻底释放了计算虚拟化的威力，极大提高了应用的维护效率，降低了云计算应用开发的成本！使用 Docker，可以让应用的部署、测试和分发都变得前所未有的高效和轻松！
 
@@ -26,8 +26,6 @@
 
 ### 在线阅读
 
-> 推荐访问官方 GitBook，体验最佳。
-
 *   **GitBook**: [yeasy.gitbook.io/docker_practice](https://yeasy.gitbook.io/docker_practice/)
 *   **GitHub**: [github.com/yeasy/docker_practice](https://github.com/yeasy/docker_practice/blob/master/SUMMARY.md)
 *   **Mirror**: [docker-practice.com](https://vuepress.mirror.docker-practice.com/)