Ruby 4.0 Moves Pathname to Core; Improved Docs Coming in Ruby 4.1

Ruby 4.0 has promoted the Pathname class from a standard library to the language's core, making it more accessible to developers. Pathname offers a unified interface to methods spread across File, FileTest, Dir, and FileUtils, reducing the need to track which class or module handles which operation. A contributor has completed a full rewrite of the Pathname documentation, reviewed by Peter Zhu, which will ship with Ruby 4.1 later this year. The updated docs provide local descriptions and examples for each method, replacing the previous approach of linking out to underlying methods in other classes. A new class-level overview and a 'What's Here' section have also been added to improve navigability.