refactor: replace doom-enlist with ensure-list

doom-enlist is now a deprecated alias for ensure-list, which is built
into Emacs 28.1+ and is its drop-in replacement. We've already
backported it for 27.x users in doom-lib (in 4bf4978).

Ref: 4bf49785fd

modules/tools/biblio/config.el

@@ -7,7 +7,7 @@
   :defer t
   :config
   (setq org-cite-global-bibliography
-        (doom-enlist
+        (ensure-list
          (or (bound-and-true-p citar-bibliography)
              (bound-and-true-p bibtex-completion-bibliography)))
         ;; Setup export processor; default csl/citeproc-el, with biblatex for