### What?
The `plugin-nested-docs` returns an array of breadcrumbs - the
`resaveChildren` file accidentally processed the breadcrumbs twice, once
where the data is updated and once within the `populateBreadcrumbs`
function which was causing the objects to be double nested.
### How?
Removes the extra nesting from `resaveChildren` file and allows the
`populateBreadcrumbs` to return the final data.
Fixes#10855
d92c0009ed