Add default keybinding for accessing recently used files

Since `counsel-switch-buffer` has been replaced by the plain
`switch-to-buffer`, recently used files are not shown there anymore, so
let's make `recentf` easier to access.

NB: `consult` also provides a function akin to `counsel-switch-buffer`,
so maybe this keybinding will not be that relevant anymore in the
future.

init.el

@@ -3018,6 +3018,7 @@ eventuelly be set to nil, however)."
   (bind-key "C-c n i" #'org-roam-node-insert)
   (bind-key "C-c n c" #'org-roam-capture)
   (bind-key "C-c o" #'hydra-org-custom/body)
+  (bind-key "C-c r" #'recentf)
   (bind-key "C-c t" #'hydra-toggle/body)
   (bind-key "C-h C-f" #'find-function)
   (bind-key "C-h C-k" #'find-function-on-key)