(defvar diff-hl-dired-types
  (->> (my-get-faces-matching-regexp "^diff-hl-dired-")
       (--map (->> it
                   symbol-name
                   (replace-regexp-in-string "^diff-hl-dired-" "")
                   intern))
       (cons nil)))

I forgot this fragment

    (defun my-get-faces-matching-regexp (regexp)
      (cl-loop for sym being the symbols
               when (facep sym)
               when (string-match-p regexp (format "%s" sym))
               collect sym))

or you can do this

    (setq diff-hl-dired-types
          '(nil insert delete unknown ignored change))