* lisp/org-footnote.el (org-footnote-auto-label):
(org-footnote-auto-adjust): Use simpler :safe value.
The point of the :safe value is to determine if the variable is safe,
not to check correctness of its value. Besides, lambda functions
appear as the following in *Help* buffer:
This variable is safe as a file local variable if its value
satisfies the predicate which is a byte-compiled expression.
which is not particularly clear. Let's keep :safe values simple.