- 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.