Extend nested summary behavior to the by_path strategy

[opposable-crumbs]

Issues

• I have checked existing issues and there are no existing ones with the same request.

Feature description

In #1144 Neorg added the ability to generate dotted categories which show up as nested headings in generated summaries. This is super useful, but it would be great if the by_path strategy behaved the same way. For example, given a workspace root of ~/notes, ~/notes/foo/bar/note.norg would generate the summary

* Summary
** Foo
*** Bar
   - {:$/foo/bar/note:}[Note]

In the current implementation it seems the category is just chosen as the immediate parent of the file.

Help

Yes

Implementation help

I'd be happy to take a crack at this, but if this would be classified as a breaking change I'd need some direction as to how those are usually handed in Neorg.