All the patterns that calls `newsticker--lists-intersect-p' in
lisp/net/newst-plainview.el like:

(newsticker--lists-intersect-p
 (get-text-property (point) 'invisible)
  buffer-invisibility-spec)

Can be replace by `(invisible-p (point))' accordingly to reduce
boilerplate.

This patch would also remove the definition of
`newsticker--lists-intersect-p' from lisp/net/newst-backend.el
since is it not referenced elsewhere.

---
ldb