Add @DeepLinkModuleRegistry marker annotation to generated registries

[donkeytronkilla]

Would it be possible to add a marker annotation (suggesting @DeepLinkModuleRegistry) to the registry types which are generated from @DeepLinkModule annotated types (I'd be happy to help contribute the change)? My use case is I want to be able to aggregate instances of the generated registries from multiple gradle modules into a single Dagger Multibinding so they can be injected into my DeepLinkDelegate. However, I want to automate the Dagger Multibinding contribution code with my own annotation processor, so I need an annotation on the generated registries to trigger a kapt round. Using KSP to initiate code generation from arbitrary symbols is not currently an option for me.