custom head not working

i tried like mentioned in https://github.com/alanorth/hugo-theme-bootstrap4-blog/pull/17 but that was not working

i created /home/me/Downloads/website/layouts/partial/head-custom.html with content "TEST"
so i would expect somewhere a "TEST" in the source, but there was nothing.

my root of the website is for testing currently at /home/me/Downloads/website 