On older org-mode versions, org lists are lists of lists of only one
element, so that
- a
- b
- c
translates as
(("a") ("b") ("c"))
But in more recent versions, the same list translates as
("a" "b" "c")
This commit handles both situations, as my local Emacs version follows
the latter behaviour but the Emacs version available in my CI workflow
follows the former behaviour.