Add after-delete-frame-functions

Add after-delete-frame-functions

Instead of working around the behavior delete-frame-functions, just
add an after-delete-frame-functions hook.

* doc/lispref/frames.texi (Deleting Frames): Document
`after-delete-frame-functions'.

* etc/NEWS: Mention `after-delete-frame-functions'.

* lisp/frame.el (blink-cursor--should-blink):
(blink-cursor--rescan-frames, blink-frame-mode): Get rid of the
ugly ignored-frame parameter and switch from
`delete-frame-functions' to `after-delete-frame-functions'.

* src/frame.c (syms_of_frame): New variable
`after-delete-frame-functions'.
(delete_frame): Use it.