[ISSUE][DOCS] Incorrect documentation on class reflection in behavior context

[lgleim]

Describe the issue

The Behavior Context documentation for classes states that one should specify base classes via a second template argument if applicable, however the current implementation only supports a single template argument.

Impacted page(s)

https://development--o3deorg.netlify.app/docs/user-guide/programming/components/reflection/behavior-context/#classes

Expected experience

1. That the limited documentation for the (anyway hard to grasp reflection system) is correct.
2. A proper explanation how to deal with reflecting hierarchies of classes

[lgleim]

@lemonade-dm Since you committed the BehaviorClassBuilder, could you by any chance provide some insights on what the proper resolution to this could be?

[lemonade-dm]

Actually the documentation for the BehaviorContext class has always been incorrect.
It never accepted the base class as a template parameter. Only the SerializeContext supplied base classes through the template parameters.

Instead the BehaviorContext gathers the Base Classes through using the AZ RTTI system by querying the base classes recursively associated with the primary registered class T rtti info via a call to AZ::RttiEnumHierarchy.

As the RTTI hierarchy is setup through the AZ_RTTI macro when creating a class, any class that uses macro has its base classes visited recursively.

If a class doesn't specify the AZ_RTTI macro, then any base class hierarchy will not be known to the BehaviorContext.