Indicate that absolute URLs are needed for search

[peterdesmet]

Getting started suggests to start with usethis::use_pkgdown(). This sets _pkgdown.yml to

url: ~
template:
  bootstrap: 5

I thought ~ was the recommended way to set the url: if I change domain name, I don't have to edit this file. I recently discovered however that for a website like org.github.io/my_package search results will link to the incorrect page at org.github.io, ignoring my_package. This issue was reported in #1945, with the suggested fix to provide the domain name in url.

Indeed, this is indicated in Getting started, but I think it might be good to indicate search is one of the functions that requires absolute URLs.

---

The current example in the documentation is:

url: https://pkgdown.r-lib.org

Perhaps it is more useful to provide an non-root domain example, which is typical for users who host their pkgdown site from GitHub Pages (e.g. https://my_org.github.io/my_package). This could then also provide guidance on whether to use an ending slash or not:

url: https://example.com/mypackage