* lisp/outline.el (outline-minor-mode-insert-buttons): New defvar-local.

* lisp/outline.el (outline-minor-mode-insert-buttons): New defvar-local.

(outline--make-button-overlay, outline--insert-open-button)
(outline--insert-close-button): Insert button when
outline-minor-mode-insert-buttons is non-nil, otherwise
put an overlay with before-string.  (bug#57813)

* lisp/help.el (describe-bindings): Set buffer-local
outline-minor-mode-insert-buttons to t.

* lisp/textmodes/emacs-news-mode.el (emacs-news--mode-common):
Set buffer-local outline-minor-mode-use-margins to t.  Don't set
outline-regexp for leading spaces because now spaces are not added
in the NEWS buffer.