Add hereditary option to as_object_map. This automatically apply as_object_map to the values of the map when the values are "plain old objects".

This behavior is slightly naive but I think it will satisfy most people who have requested this feature.


- [x] Add a [CHANGELOG](https://github.com/pyodide/pyodide/blob/main/docs/project/changelog.md) entry
- [x] Add / update tests
- [x] Add new / update outdated documentation

package:
  name: pkg_test_graph2
  version: "1.0.0"
source:
  path: src

package:
  name: pkg_test_graph2
  version: "1.0.0"
source:
  path: src
