Articles dropdown starts with an empty divider (Bootstrap 5) #3033

With Bootstrap 5, when the first articles: section has a navbar: heading, the Articles dropdown starts with an empty divider. This is the same problem as #1319, which was fixed for Bootstrap 4 only.

template:
  bootstrap: 5

articles:
- title: Working with models
  navbar: Working with models
  contents:
  - prompt-design
  - structured-data
  - tool-calling
- title: Building with ellmer
  navbar: Building with ellmer
  contents:
  - programming
  - streaming-async
  - otel

The generated menu:

<ul class="dropdown-menu" aria-labelledby="dropdown-articles"><li><hr class="dropdown-divider"></li>
  <li><h6 class="dropdown-header" data-toc-skip>Working with models</h6></li>
  ...

navbar_articles() adds a separator before every section heading, including the first one:

The empty space also matters because .dropdown-menu has max-height: 280px. In the screenshot, the last link ("Monitoring with OpenTelemetry") is pushed below the fold and only shows if you scroll the menu.

A possible fix is to skip the separator for the first section, for example by passing index into the check: if (!is.null(section$navbar)) list(if (index > 1) menu_separator(), menu_heading(section$navbar)).

Seen with pkgdown 2.2.1 and on main.