Fix about_proxy_object_project koan

* proxy object is generic, it only catches
  method calls, and traps NoMethodErrors, and
  the count of calls.

* Useful as stand-in block of code, where
  method calls are logged even without working
  code.

* used ternary syntax for the first time on
  line 29!

[#54145707]
Update about_to_str.rb
Merge pull request #30 from bayendor/54145707_about_proxy_object_project_master

Fix about_proxy_object_project koan

[Delivers #54145707]