[Emacs] Move out function definition for `phundrak/find-org-files'

This commit promotes a lambda to an actual function and moves it to the
custom functions part.

org/config/emacs.org

@@ -1423,6 +1423,42 @@
         '("st"))
     #+END_SRC
 
+*** ~phundrak/find-org-file~
+    :PROPERTIES:
+    :CUSTOM_ID: User_Configuration-Custom_functions-phundrakfind-org-file-029040a5
+    :END:
+    There are lots of  files which I want to be able to  quickly open. I used to
+    have one shortcut for  each one of these files, but as  their number grew, I
+    decided to switch to helm for my  file selector which will be called by only
+    one common shortcut. Most of my files will be located in =~/org=, but I have
+    some conlanging files which are located in =~/Documents/conlanging=, and all
+    my  university notes  are in =~/Documents/university=. Let’s  declare these
+    directories in a variable:
+    #+BEGIN_SRC emacs-lisp
+      (setq phundrak/org-directories '("~/org"
+                                       "~/Documents/university"
+                                       "~/Documents/conlanging"))
+    #+END_SRC
+
+    With this established, let’s write some emacs-lisp that will allow me to get
+    a list of all these files and select them through helm. Be aware that I will
+    be using some functions from third party packages, such as [[https://github.com/rejeep/f.el][f.el]] and [[https://github.com/magnars/dash.el][dash]].
+    #+BEGIN_SRC emacs-lisp
+      (defun phundrak/find-org-file ()
+        (interactive)
+        (find-file
+         (helm
+          :sources (helm-build-sync-source "org files"
+                     :candidates (-mapcat
+                                  (lambda (path)
+                                    (f-files path
+                                             (lambda (file) (equal (f-ext file) "org"))
+                                             t))
+                                  phundrak/org-directories)
+                     :fuzzy-match t)
+          :buffer "*org files*")))
+    #+END_SRC
+
 ** Emacs builtins
    :PROPERTIES:
    :CUSTOM_ID: User_Configuration-Emacs_builtins-7822b8dd
@@ -2950,39 +2986,9 @@
     :PROPERTIES:
     :CUSTOM_ID: User_Configuration-Shortcuts-Files-206c2126
     :END:
-    There are lots of  files which I want to be able to  quickly open. I used to
-    have one shortcut for  each one of these files, but as  their number grew, I
-    decided to switch to helm for my  file selector which will be called by only
-    one common shortcut. Most of my files will be located in =~/org=, but I have
-    some conlanging files which are located in =~/Documents/conlanging=, and all
-    my  university notes  are in =~/Documents/university=. Let’s  declare these
-    directories in a variable:
-    #+BEGIN_SRC emacs-lisp
-      (setq phundrak/org-directories '("~/org"
-                                       "~/Documents/university"
-                                       "~/Documents/conlanging"))
-    #+END_SRC
-
-    With this established, let’s write some emacs-lisp that will allow me to get
-    a list of all these files and select them through helm. Be aware that I will
-    be using some functions from third party packages, such as [[https://github.com/rejeep/f.el][f.el]] and [[https://github.com/magnars/dash.el][dash]].
     #+BEGIN_SRC emacs-lisp
       (spacemacs/declare-prefix "of" "open org file")
-      (spacemacs/set-leader-keys
+      (spacemacs/set-leader-keys "of" 'phundrak/find-org-file)
-        "of"
-        (lambda ()
-          (interactive)
-          (find-file
-           (helm
-            :sources (helm-build-sync-source "org files"
-                       :candidates (-mapcat
-                                    (lambda (path)
-                                      (f-files path
-                                               (lambda (file) (equal (f-ext file) "org"))
-                                               t))
-                                    phundrak/org-directories)
-                       :fuzzy-match t)
-            :buffer "*org files*"))))
     #+END_SRC
 
     I also have a shortcut for ~helm-locate~ in  case I need to find a file that