feature/lookup: fix +lookup/definition not fetching the correct identifier
feature/lookup: fix +lookup/definition not fetching the correct identifier

Some xref backends have specialized thing-at-point implementations (such
as haskell's dante's xref backend), this fix uses them to fetch the
identifier at point.

hlissner/doom-emacs,hlissner/doom-emacs,hlissner/doom-emacs,UndeadKernel/emacs_doom,UndeadKernel/emacs_doom,hlissner/.emacs.d,UndeadKernel/emacs_doom,UndeadKernel/emacs_doom,hlissner/.emacs.d,hlissner/doom-emacs,UndeadKernel/emacs_doom,hlissner/.emacs.d,UndeadKernel/emacs_doom,hlissner/doom-emacs,hlissner/.emacs.d,hlissner/doom-emacs,hlissner/.emacs.d,hlissner/doom-emacs,hlissner/.emacs.d,UndeadKernel/emacs_doom,hlissner/.emacs.d,hlissner/.emacs.d