Missing Documentation: Model Service - $_type_classes

[RK311y]

Suggested Change

Add documentation to describe $_type_classes property for the Model Service. The use case I have found which demonstrates this can be found in the Site Model

Note: While writing this issue, I noticed that this model now does not actually use a custom $_type_classes for any of its properties: ExpressionEngine\Service\Model\Column\CustomType

I am assuming that this change happened between version 5 and 6.

Reasoning

The documentation does describe Typed Columns but it does not describe that Composite Types can be custom.

Example of a custom composite type: ChannelPreferences

Additional context

I assume that the Site Model no longer utilizes these custom $_type_classes because information stored in these variables is only accessible once the model has been loaded, therefore these property values cannot be used when filtering for models. Is this correct?

Also, I have not looked deeper into this, but the Site Model was the only model I was familiar with that used this type of Variable Column. My next question is whether or not the uses of $_type_classes are being phased out in a later version?