feat(fold): add +fold-ellipsis var

Bring *some* consistency to the text display when text is
ellided/folded.

Close: #7743
Co-authored-by: seanfarley <seanfarley@users.noreply.github.com>

modules/editor/fold/autoload/hideshow.el

@@ -30,7 +30,8 @@
                          'empty-line
                          'vimish-fold-fringe))))
     (overlay-put
-     ov 'display (propertize "  [...]  " 'face '+fold-hideshow-folded-face))))
+     ov 'display (propertize +fold-ellipsis
+                             'face '+fold-hideshow-folded-face))))
 
 
 ;;

modules/editor/fold/config.el

@@ -1,5 +1,17 @@
 ;;; editor/fold/config.el -*- lexical-binding: t; -*-
 
+(defcustom +fold-ellipsis " [...] "
+  "The ellipsis to show for ellided regions (folds).
+
+`org-ellipsis', `truncate-string-ellipsis', and `ts-fold-replacement' are set to
+this."
+  :type 'string
+  :group '+fold)
+
+
+;;
+;;; Global config
+
 (when (modulep! :editor evil)
   ;; Add vimish-fold, outline-mode & hideshow support to folding commands
   (define-key! 'global
@@ -18,9 +30,15 @@
       "zd" #'vimish-fold-delete
       "zE" #'vimish-fold-delete-all)))
 
+(after! org
+  (setq org-ellipsis +fold-ellipsis))
+
+(after! mule-util
+  (setq truncate-string-ellipsis +fold-ellipsis))
+
 
 ;;
-;; Packages
+;;; Packages
 
 (use-package! hideshow ; built-in
   :commands (hs-toggle-hiding
@@ -97,5 +115,5 @@
                                                 :box nil
                                                 :inherit font-lock-comment-face
                                                 :weight light))
-  (setq ts-fold-replacement "  [...]  ")
+  (setq ts-fold-replacement +fold-ellipsis)
   (global-ts-fold-mode +1))