Merge pull request #25084 from y-yagi/fix_module_name

fix module name [ci skip]

guides/source/testing.md

@@ -1289,5 +1289,5 @@ end
 assert_equal Date.new(2004, 10, 24), user.activation_date # The change was visible only inside the `travel_to` block.
 ```
 
-Please see [`ActiveSupport::TimeHelpers` API Documentation](http://api.rubyonrails.org/classes/ActiveSupport/Testing/TimeHelpers.html)
+Please see [`ActiveSupport::Testing::TimeHelpers` API Documentation](http://api.rubyonrails.org/classes/ActiveSupport/Testing/TimeHelpers.html)
 for in-depth information about the available time helpers.