Merge pull request #607 from rspec/fix-ruby-head

Fix warnings on Ruby 3.4.0

Author: JonRowe

spec/rspec/support/differ_spec.rb

@@ -1,6 +1,5 @@
 # encoding: utf-8
 require 'spec_helper'
-require 'ostruct'
 require 'timeout'
 require 'rspec/support/spec/string_matcher'
 

spec/rspec/support_spec.rb

@@ -164,7 +164,7 @@ def self.to_s
 
       context 'with an object having a singleton class' do
         let(:object) do
-          object = 'foo'
+          object = String.new('foo')
 
           def object.some_method
           end