lang/org: add TODO keywords & fontification

+ Adds LOOP and IDEA to primary todo keywords.
+ Adds OKAY, YES, and NO sequence.
+ Specially fontifies NO and KILL with special "cancelled" face to
  indicate an aborted/rejected task.
+ Specially fontifies PROJ to set it apart.

modules/lang/org/config.el

@@ -140,14 +140,17 @@ Is relative to `org-directory', unless it is absolute. Is used in Doom's default
   (with-no-warnings
     (custom-declare-face '+org-todo-active  '((t (:inherit (bold font-lock-constant-face org-todo)))) "")
     (custom-declare-face '+org-todo-project '((t (:inherit (bold font-lock-doc-face org-todo)))) "")
-    (custom-declare-face '+org-todo-onhold  '((t (:inherit (bold warning org-todo)))) ""))
+    (custom-declare-face '+org-todo-onhold  '((t (:inherit (bold warning org-todo)))) "")
+    (custom-declare-face '+org-todo-cancel  '((t (:inherit (bold error org-todo)))) ""))
   (setq org-todo-keywords
         '((sequence
            "TODO(t)"  ; A task that needs doing & is ready to do
            "PROJ(p)"  ; A project, which usually contains other tasks
+           "LOOP(r)"  ; A recurring task
            "STRT(s)"  ; A task that is in progress
            "WAIT(w)"  ; Something external is holding up this task
            "HOLD(h)"  ; This task is paused/on hold because of me
+           "IDEA(i)"  ; An unconfirmed and unapproved task or notion
            "|"
            "DONE(d)"  ; Task successfully completed
            "KILL(k)") ; Task was cancelled, aborted or is no longer applicable
@@ -156,14 +159,21 @@ Is relative to `org-directory', unless it is absolute. Is used in Doom's default
            "[-](S)"   ; Task is in progress
            "[?](W)"   ; Task is being held up or paused
            "|"
-           "[X](D)")) ; Task was completed
+           "[X](D)")  ; Task was completed
+          (sequence
+           "|"
+           "OKAY(o)"
+           "YES(y)"
+           "NO(n)"))
         org-todo-keyword-faces
         '(("[-]"  . +org-todo-active)
           ("STRT" . +org-todo-active)
           ("[?]"  . +org-todo-onhold)
           ("WAIT" . +org-todo-onhold)
           ("HOLD" . +org-todo-onhold)
-          ("PROJ" . +org-todo-project)))
+          ("PROJ" . +org-todo-project)
+          ("NO"   . +org-todo-cancel)
+          ("KILL" . +org-todo-cancel)))
 
   (defadvice! +org-display-link-in-eldoc-a (&rest _)
     "Display full link in minibuffer when cursor/mouse is over it."