In https://docs.ruby-lang.org/en/master/Forwardable.html, in "Notes," text `forwardable.rb` links to https://docs.ruby-lang.org/en/master/lib/forwardable_rb.html.
In https://docs.ruby-lang.org/en/master/Forwardable.html, in "Notes," text
forwardable.rblinks to https://docs.ruby-lang.org/en/master/lib/forwardable_rb.html.