bug#41129: outline-mode: New keybindings for demote/promote/move-subtree

[Juri Linkov]

>> Should these four bindings be on outline-minor-mode-cycle-map or
>> on outline-minor-mode-map?  They don't have to do with cycling.
>
> Juri suggested putting them on the former because they'd be too
> disturbing in the main map -- M-<right> etc are bound to navigation
> commands in editable buffers.

Actually I suggested these bindings only for personal customization
for anyone who needs to edit heading levels because these bindings
are too intrusive to be used by default in the cycling map.
It already takes the TAB key from users, and taking more keys is too much
for the cycling map.  To be able to add editing keys to outline-minor-mode
they need to be on some separate map such as outline-minor-mode-edit-map.