override inspect() of ref and lazy to make description readable

[shinji-yoshida]

This PR makes description readable.

Currently, failed spec looks like:

Failures:

  1) RSpec::Parameterized lazy a: #<RSpec::Parameterized::RefArg:0x00007fd356a1ff50 @symbol=:one>, b: #<RSpec::Parameterized::RefArg:0x00007fd356a1ff28 @symbol=:four>, answer: #<RSpec::Parameterized::LazyArg:0x00007fd356a1fed8 @block=#<Proc:0x00007fd356a1fe88@/Users/shinji_yoshida/workspace/rspec-parameterized/spec/parametarized_spec.rb:224>> define two and three after where block fail
                                 Failure/Error: expect(a + b + 1).to eq answer

expected: 5
got: 6

(compared using ==)
# ./spec/parametarized_spec.rb:238:in `block (5 levels) in <top (required)>'

After This PR applied, failed spec will look like:

Failures:

  1) RSpec::Parameterized lazy a: one, b: four, answer: lazy { two + three } define two and three after where block fail
Failure/Error: expect(a + b + 1).to eq answer

expected: 5
got: 6

(compared using ==)
# ./spec/parametarized_spec.rb:238:in `block (5 levels) in <top (required)>'

[joker1007]

Thanks!!
I apologize for the late response.
It looks good to me.