pkgdown includes three helpful pkgdown::template_*() functions to generate
the navbar, reference, and article YAML for the _pkgdown.yml file.
pkgdown_template() is a wrapper function that runs all three, combines
them, and converts them to a yml object. You may also pass
pkgdown::template_*() functions to as_yml() to convert the individual
sections. pkgdown_template() is particularly useful with
use_pkgdown_yml() to write directly to the _pkgdown.yml file.