bug#68824: treesitter support for outline-minor-mode

[Juri Linkov]

>> >>> Then maybe just move the text about outline-search-function to the
>> >>> place where you describe treesit-outline-predicate?
>> >> 
>> >> 'outline-search-function' is unsuitable for "Tree-sitter Major Modes".
>> > 
>> > All of this thread clearly indicates otherwise.
>> 
>> The real problem is probably that outline-minor-mode’s api wasn’t
>> described in the Elisp manual (Imenu, OTOH, has a node in Elisp
>> manual). I think we can create a node for outline in (elisp)Modes (that’s
>> where the node for Imenu is). We can start out with only
>> outline-search-function in there, and over time populate it with
>> outline-level, outline-regexp, etc.
>
> That'd be fine by me.  But since Juri said he was uncomfortable with
> such a short node, I tried to suggest alternative ideas.  If having a
> short new node is deemed our best option, then let's do that.

Ok, let's add a new node.

This is now done and pushed to master.

Please check if everything is correct.