bug#66485: 13.2.1; preview-scale-function should be safe for numberp

[Arash Esbati]

"Philipp G. Haselwarter" <philipp@haselwarter.org> writes:

> ;;;###autoload
> (put 'preview-scale-function 'safe-local-variable 'numberp)
>
> should be added in preview.el after the definition of
> preview-scale-function.

I think this is a reasonable change.  What do others think?

Best, Arash