Table of contents within a chapter

[steveklabnik]

Originally filed by @SimonSapin at rust-lang/rust#40087

It looks like https://doc.rust-lang.org/nightly/reference.html hasn’t been updated yet as of this writing, but in my local copy of the docs reference.html says “We've split up the reference into chapters. Please find it at its new home here.” with a link to reference/index.html.

This new format has a side bar with a table of content, but that ToC has coarser granularity than it used to. As far as I can tell, it has a link for each “chapter” (part of the book that requires navigation to another URL), but I can’t find a ToC for sections within a chapter. reference/expressions.html for example has many sub-sections, to a per-chapter ToC would help a lot.

This is probably a feature request for tool that generates this kind of documentation, but I’m not sure what it is. I’ve vaguely heard of rustboot and mdbook, is this one on these? Are they related? Which issue tracker should be used?

CC @steveklabnik