fix Support type-restricted args #13

[keizo3]

fixes #13

I tried to use it as follows
(I made it possible to specify a type)

module Notifier
  def self.notify(message : String)
  end
end

create_module_mock Notifier do
  mock self.notify(message : String)
end

allow(Notifier).to receive(self.notify("John")).and_return("Just great!")
Notifier.notify("John")    # => "Just great!"