Allow traits to override the class

Problem this feature will solve

I'm refactoring code to use Single Table Inheritance and I'd really like to be able to override the class on each trait as opposed to defining a completely new factory for each subclass.

Desired solution

From an API perspective providing options to the trait call would be nice

factory :generator_performance do
    trait :reactive_power_capability, class: '...' do
    end
end

Alternatives considered

I'll either extract these to concrete classes now OR try the solution referenced at https://dev.to/epigene/simple-trick-to-make-factorybot-work-with-sti-j09

Additional context

In my case I have an ActiveRecord Model that represents a bunch of different documents. The current model definition and its validations are loose enough to allow for the many shapes but it is a mess. There is a large core of shared properties. Currently each of the document types are defined as FactoryBot traits.

No files or tests are named in the issue. Start by tracing the existing trait API and how FactoryBot resolves a factory's class, then compare that path with the proposed Single Table Inheritance use case. Done means a trait can override its class through the proposed option syntax without requiring a separate factory, with coverage for that behavior.