Manual index page

[zeileis]

One feature that I like about pkgdown and am still missing in altdoc is the possibility to structure the documentation in the YAML configuration which will then generate an index page with sections.

As an example consider the "Reference" landing page of https://Formula.R-Forge.R-project.org/ which looks like this:

This is generated automatically based on this section in the YAML configuration:

reference:
  - title: "Extended model formulas"
    contents: 
      - Formula
  - title: "Methods"
    contents: 
      - model.frame.Formula

Of course, with so few individual pages this structure is not so important but for bigger packages it is very useful.

In altdoc/quarto_website.yml one could use a similar structure (possibly with man: or documentation: instead of reference:) and then generate a man/index.qmd from it. Additionally, the same structure could go in the $ALTDOC_MAN_BLOCK (see also #325 on using navbar and/or sidebar for this).

I'm happy to help with this but - as discussed with @etiennebacher in person today - I would need guidance where to put what...

P.S.: Thank you both for the amazing package, I'm a big fan!