- Bump project version to 1.3.9.
- Move HashMapHelper to Collections namespace.
- Simplify UnsafeList<T>.AddRange to use only Span<T>.
- Add Remove overloads with out parameter to UnsafeSlotMap<T> and UnsafeSparseSet<T>.
- Improve MemoryLeakException stack trace formatting.
- Remove obsolete commented code in IJobSPMD.cs.