Custom menu with direct links

When a top-level menu entry has no children, it renders as a plain <a> link in the navigation bar. This is the right pattern for short menus where each destination is a single page.

The navigation above is driven by the demo_direct menu defined in menus.en.toml and activated on this page with:

main_menu: "demo_direct"

[[demo_direct]]
    name = "Home"
    url = "/"
    weight = 1

[[demo_direct]]
    name = "Examples"
    url = "/examples/"
    weight = 2

[[demo_direct]]
    name = "Changelog"
    url = "/changelog/"
    weight = 3