Make some tweaks to Org mode stuff

Namely, open ~/exo/index.org on start-up, and get rid of the message in
the *Scratch* buffer.

config.org

@@ -225,15 +225,26 @@ needs to be set up to install them if they aren't already.
       (require 'org-tempo))
   #+end_src
 
-  Org is better suited as scratch space than Emacs lisp, I'd say.
+  Org is better suited as scratch space than Funamental, I'd say.
 
   #+begin_src emacs-lisp
     (setq initial-major-mode 'org-mode)
+    (setq initial-scratch-message "")
   #+end_src
 
-  Set up a keybinding for =org-agenda= and tell it where to look. I
+  I always want [[file:~/exo/index.org][~/exo/index.org]] to open on start-up, as that's where I
+  keep links to whatever I happen to be doing at any given time; one
+  does that by setting [[help:initial-buffer-choice][initial-buffer-choice]]
+
+  #+begin_src emacs-lisp
+    (setq initial-buffer-choice "~/exo/index.org")
+  #+end_src
+
+** Agenda
+
+   Set up a keybinding for [[help:org-agenda][org-agenda]] and tell it where to look. I
    have a bunch of org documents making up a sort of wiki which I keep
-  under =~/exo=.
+   under [[file:~/exo][~/exo]].
 
    #+begin_src emacs-lisp
      (define-key global-map (kbd "C-c a") 'org-agenda)
@@ -249,7 +260,7 @@ needs to be set up to install them if they aren't already.
 
    I often want to see TODO items that aren't scheduled to decide on
    something to do (if I've already done all the scheduled things), so
-  it's nice for =org-agenda= to have an option for that.
+   it's nice for [[help:org-agenda][org-agenda]] to have an option for that.
 
    #+begin_src emacs-lisp
      (setq org-agenda-custom-commands