New mode outline-cycle-minor-mode with Orgmode-like TAB cycling on headings

New mode outline-cycle-minor-mode with Orgmode-like TAB cycling on headings

* lisp/outline.el (outline-mode-cycle-map): New keymap from outline-mode-map.
(outline-mode-map): Inherit from outline-mode-cycle-map.
(outline-font-lock-keywords): Append keymap and face depending on
'outline-minor-mode-cycle' and 'outline-minor-mode-highlight'.
(outline-minor-mode-cycle, outline-minor-mode-highlight): New variables.
(outline-minor-mode-highlight-buffer): New function.
(outline-minor-mode): Handle 'outline-minor-mode-cycle' and
'outline-minor-mode-highlight'.
(outline-cycle-minor-mode, outline-cycle-highlight-minor-mode):
New minor modes (bug#45147).

* etc/compilation.txt:
* etc/grep.txt:
Enable outline-cycle-highlight-minor-mode.