Allow pretty print width to be injectable

[JoshCheek]

Eg in POODR, we have the below example, but since the pp width is hard-coded to 74, we can't reproduce this example.

class Bicycle
  attr_reader :size, :tape_color

  def initialize(args)
    @size = args[:size]
    @tape_color = args[:tape_color]
  end

  def spares
    { chain: '10-speed',
      tire_size: '23',
      tape_color: tape_color,
    }
  end

end

bike = Bicycle.new(
  size: 'M',
  tape_color: 'red'
)

bike.size # => "M"
bike.spares
# => {:chain=>"10-speed",
#     :tire_size=>"23",
#     :tape_color=>"red"}

[JoshCheek]

(page 108)