Fix void string-edit-mode

problem:
Trying to describe a key: `C-h k` `j`
shows:
Symbol’s value as variable is void: string-edit-mode

solution
Don't defer the string-edit package.

layers/+spacemacs/spacemacs-editing/packages.el

@@ -482,7 +482,6 @@
 
 (defun spacemacs-editing/init-string-edit ()
   (use-package string-edit
-    :defer t
     :init
     (spacemacs/set-leader-keys "xe" 'string-edit-at-point)
     (spacemacs/set-leader-keys-for-minor-mode 'string-edit-mode