Ruby 4.0 released

Once again there is a brand-new release under the tree from the Ruby programming-language project: Ruby 4.0 has been released with many new features and improvements. Notable changes include the experimental Ruby Box feature for in-process isolation of classes and modules, a new just-in-time compiler called ZJIT, and improvements to Ruby's parallel-execution mechanism (Ractor). There are a number of language changes as well. See the documentation for Ruby 4.0 for more.