lang/ess: remove redundant line-number display hook
lang/ess: remove redundant line-number display hook

`display-line-numbers-mode` is already in prog-mode-hook and ess-mode is
derived from prog-mode.

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