Incorrect values in arrows kata

[walterlatimer]

  it('one parameter can be written without parens', () => {
    var func = p => param - 1;
    assert.equal(func(23), 24);
  });

Pretty sure func(23) should be func(25).

[wolframkriesing]

Hi Walter,

actually the second line can be changed too, so there is no need to adjust the assert-line.
the function may also become var func = param => param + 1; is one way

[walterlatimer]

Hi Wolfram!

While true, that isn't the point of the kata, which is to understand how arrows work.

[wolframkriesing]

as you can see here walterlatimer@4adb956 I intentionally changed it, since I develop the katas so that they pass first, but will merge the attached PR now, since I agree on your point ... thx