Fix error message

* lisp/org.el (org-kill-line): Fix error message.

lisp/org.el

@@ -23694,7 +23694,9 @@ depending on context."
 	       org-ctrl-k-protect-subtree
 	       (or (eq org-ctrl-k-protect-subtree 'error)
 		   (not (y-or-n-p "Kill hidden subtree along with headline? "))))
-      (user-error "C-k aborted as it would kill a hidden subtree"))
+      (user-error
+       (substitute-command-keys
+	"`\\[org-kill-line]' aborted as it would kill a hidden subtree")))
     (call-interactively
      (if (bound-and-true-p visual-line-mode) 'kill-visual-line 'kill-line)))
    ((looking-at ".*?\\S-\\([ \t]+\\(:[[:alnum:]_@#%:]+:\\)\\)[ \t]*$")