Source Generator Improvement Proposal

[Seeker1437]

Contains changes I meant to PR before parting ways.

Add support for explicit service types, open generics, and keyed service registration

Register as self, singleton

[ServiceRegistration(Lifetime.Singleton)]
public class MyService { }

Register as interface, scoped

[ServiceRegistration(Lifetime.Scoped, registerInterfaces: true)]
public class MyService : IMyService { }

Register explicit interface, scoped

[ServiceRegistration(Lifetime.Scoped, ServiceType = typeof(IMyService))]
public class MyService : IMyService { }

Register open generic repository as IRepository, scoped

[ServiceRegistration(Lifetime.Scoped, ServiceType = typeof(IRepository<>))]
public class Repository<T> : IRepository<T> { }

Register keyed service (Vip) as IDiscountService

[ServiceRegistration(
    Lifetime.Singleton,
    ServiceType = typeof(IDiscountService),
    Key = "Vip")]
public class VipDiscountService : IDiscountService { }

Register the same implementation under multiple keys

[ServiceRegistration(Lifetime.Singleton, ServiceType = typeof(IDiscountService), Key = "Basic")]
[ServiceRegistration(Lifetime.Singleton, ServiceType = typeof(IDiscountService), Key = "Premium")]
public class DiscountService : IDiscountService { }