In an org-agenda buffer the following functions are defined and bound:
- org-agenda-todo-nextset (C-S-left)
- org-agenda-todo-previousset (C-S-right)
which change between sets of todo keywords.
Yet the following corresponding functions are missing:
- org-agenda-todo-next-keyword
- org-agenda-todo-previous-keyword
which should (if implemented) change between individual todo keywords.
If I have the following setup:
```emacs-lisp
(setq org-todo-keywords
'((sequence "TODO(t)" "|" "DONE(d)")
(sequence "NEXT(n)" "|" "WAITING(w)")))
```
There is no way to change a task to DONE using C-S-left and C-S-right
bindings alone.
What's the reason for this?
