[3.11] Datamodel: Add headings to the standard type hierarchy (GH-108146) (#108484)

* [3.11] Datamodel: Add headings to the standard type hierarchy (GH-108146)

Dedent content according to the new layout..
(cherry picked from commit 2b7bff0)

Co-authored-by: Adam Turner <[email protected]>

* Fix indentation

Author: AA-Turner