Garbage collection in Rust got a little better

The dumpster garbage collection library for Rust has been updated with significant improvements after two years. Key enhancements include making the Trace trait dyn-compatible to support trait objects inside Gc pointers, enabling dynamic dispatch while maintaining compile-time performance guarantees. A new_cyclic function simplifies creating self-referential garbage-collected structures by using a dead Gc sentinel approach that gets rehydrated after construction. These changes make dumpster more flexible and ergonomic for handling cyclic data structures and graph algorithms in Rust.