* lisp/subr.el (add-to-invisibility-spec): Tweak doc fix from
previous patch.
If `buffer-invisibility-spec' isn't a list before calling this
function, `buffer-invisibility-spec' will afterwards be a list
with the value `(t ELEMENT)'. This means that if text exists
-with non-`t' invisibility values, that text will become visible."
+that invisibility values that aren't either `t' or ELEMENT, that
+text will become visible."
(if (eq buffer-invisibility-spec t)
(setq buffer-invisibility-spec (list t)))
(setq buffer-invisibility-spec