Release v7.19.8

Fixed

• Registering generated type discovery providers no longer slows down as an application loads more assemblies. Each call now walks only the assemblies that are new since the last call, and resolves references through a lookup instead of asking every loaded assembly for its name. Before, a process that loaded or emitted an assembly between calls repeated the full walk under a process-wide lock. This is common in a spec harness that builds a service provider per spec. Cratis Studio's specs ran in 3½ minutes before this change and in 5 seconds after it.