refactor: remove doom/goto-private-*-file commands

These commands were removed in an ongoing effort to slim down Doom and
its core. The `doom/goto-private-*-file` family of commands were
redundant with `doom/open-private-config` and
`doom/find-file-in-private-config`.

lisp/lib/config.el

@@ -13,7 +13,7 @@
   "Browse your `doom-user-dir'."
   (interactive)
   (unless (file-directory-p doom-user-dir)
-    (make-directory doom-user-dir t))
+    (user-error "$DOOMDIR doesn't exist (%s)" (abbreviate-file-name doom-user-dir)))
   (doom-project-browse doom-user-dir))
 
 ;;;###autoload
@@ -22,30 +22,6 @@
   (interactive)
   (doom-project-find-file doom-user-dir))
 
-;;;###autoload
-(defun doom/goto-private-init-file ()
-  "Open your private init.el file.
-And jumps to your `doom!' block."
-  (interactive)
-  (find-file (expand-file-name doom-module-init-file doom-user-dir))
-  (goto-char
-   (or (save-excursion
-         (goto-char (point-min))
-         (search-forward "(doom!" nil t))
-       (point))))
-
-;;;###autoload
-(defun doom/goto-private-config-file ()
-  "Open your private config.el file."
-  (interactive)
-  (find-file (expand-file-name doom-module-config-file doom-user-dir)))
-
-;;;###autoload
-(defun doom/goto-private-packages-file ()
-  "Open your private packages.el file."
-  (interactive)
-  (find-file (expand-file-name doom-module-packages-file doom-user-dir)))
-
 
 ;;
 ;;; Managements

modules/config/default/config.el

@@ -375,8 +375,7 @@ Continues comments if executed from a commented line."
   ;; replaces `apropos-documentation' b/c `apropos' covers this
   "d"    nil
   "db"   #'doom/report-bug
-  "dc"   #'doom/goto-private-config-file
+  "dc"   #'doom/open-private-config
-  "dC"   #'doom/goto-private-init-file
   "dd"   #'doom-debug-mode
   "df"   #'doom/help-faq
   "dh"   #'doom/help
@@ -386,7 +385,6 @@ Continues comments if executed from a commented line."
   "dn"   #'doom/help-news
   "dN"   #'doom/help-search-news
   "dpc"  #'doom/help-package-config
-  "dpd"  #'doom/goto-private-packages-file
   "dph"  #'doom/help-package-homepage
   "dpp"  #'doom/help-packages
   "ds"   #'doom/help-search-headings