fixed bug about localized guide-key/highlight-command-regexp

The command that is matched by `guide-key/highlight-command-regexp` was not highlighted even if 
the following config was set.

```lisp
(defun guide-key/my-hook-function-for-org-mode ()
  (guide-key/add-local-guide-key-sequence "C-c")
  (guide-key/add-local-guide-key-sequence "C-c C-x")
  (guide-key/add-local-highlight-command-regexp "org-"))
(add-hook 'org-mode-hook 'guide-key/my-hook-function-for-org-mode)
```

Then, I found the cause.
`guide-key/highlight-command-regexp` is a buffer local variable but is read in the `guide-key/guide-buffer-name` buffer when execute `guide-key/popup-function`.

So, I've made `guide-key/popup-function` pass `guide-key/highlight-command-regexp` to `guide-key/get-highlight-face`.

Is this trouble a degraded bug?