Consistently test alist keys with equal in map.el

Consistently test alist keys with equal in map.el

* etc/NEWS: Announce new default behavior of map-elt and map-delete
on alists.

* lisp/emacs-lisp/map.el: Bump to version 3.2.
(map-elt): Test alist keys with equal by default.  Betray a little
bit more information in the docstring on which functions are used
for which map types.  (Bug#47368)
(map-put): Update docstring accordingly.
(map--plist-delete): Consistently test plist keys with eq.
(map-delete): Consistently test alist keys with equal.

* test/lisp/emacs-lisp/map-tests.el (test-map-elt-testfn): Update
for new map-elt behavior.
(test-map-put!-alist, test-map-delete-alist): New tests.