Add docs about `belongs_to` behavior on actions

[Paul-Bob]

Improve

Add docs about belongs_to behavior on actions, from here

[github-actions]

This issue has been marked as stale because there was no activity for the past 15 days.

[github-actions]

Closing this because there was no activity for the past 15 days. Feel free to reopen if new information pops up ✌️

[github-actions]

This issue has been marked as stale because there was no activity for the past 15 days.