[Docs] Restore Top-Level Section Navigation in Docs

[AlenkaF]

Describe the enhancement requested

While reviewing the dev documentation, I noticed that the top-level overview of each implementation, which used to be accessible via the Section navigation, is now missing following the changes in PR #46583.

That navigation made it much easier to browse and jump between subsections, so I wonder if it might make sense to keep the .. toctree:: directive with :maxdepth: 1 in docs/source/index.rst to preserve that usability.

Component(s)

Documentation

[AlenkaF]

For example:

[AlenkaF]

Similar in C++:

[AlenkaF]

cc @thisisnic @ianmcook

[thisisnic]

The change was intentional so we could link to both the docs and source more easily, but I'm not super opinionated about how we do it so don't mind. If you change it back, you'd need to find a different way to link to both docs and source.

[AlenkaF]

Appreciate the explanation! I’ll take a closer look when I get a chance—it might be tricky to solve.

[ianmcook]

@AlenkaF @thisisnic see the fix I implemented in #46784. This makes the full TOC tree show in the left menu on all the Implementations docs pages:

In addition to fixing the issue described above, I think this is arguably an improvement over the current stable docs—although the addition of an "Implementations" level to the hierarchy makes the breadcrumb nav at the top of the page wider/longer.

[ianmcook]

Preview: http://crossbow.voltrondata.com/pr_docs/46784/cpp/user_guide.html