Sub chapters as anchor links to the same chapter

[elpiel]

Problem

Currently if you want to have sub chapter that point to the same markdown as the chapter you get additional .md and .html files generated:

- [First Chapter](relative/path/to/markdown.md)
- [Second Chapter](relative/path/to/markdown2.md)
   - [Sub Chapter](relative/path/to/markdown2.md#sub-chapter)

The least we can do is not generate the html & md files and instead just point to the anchor link in summary.

I will take a look at mdbook code and see if I can open a PR regarding this.

Proposed Solution

No response

Notes

No response