Compatibility with jsonapi_include

Problem/Motivation

I use this (fantastic) module along with JSONAPI Include → . After updating to the latest (1.6) version of that module, the structure of the JSON from this module changes.

Steps to reproduce

1. Install JSONAPI Include 1.6 or higher.
2. Browse to a JSON response from this module eg /jsonapi/menu_items/main
3. Note that the structure of the menu_link_content has changed with most of the data moving up a level from being children of the 'attributes' property.

Note that JSONAPI Include already affected the structure of /jsonapi/menu_link_content/menu_link_content provided by core in the same way in previous versions. The latest update also makes it affect this modules output.

Proposed resolution

I don't think this is a bug, but it is a gotcha. Posting for exposure for others who use both modules and may be trying to workout why the data structure changed suddenly.