BitArray.to_s should output the same format as Int.to_s

[dukeraphaelng]

Currently BitArray.to_s is outputting in the format BitArray[00000]

crystal/src/bit_array.cr

Lines 212 to 226 in f0901e1

	# Creates a string representation of self.
	#
	# ```
	# require "bit_array"
	#
	# ba = BitArray.new(5)
	# ba.to_s # => "BitArray[00000]"
	# ```
	def to_s(io : IO) : Nil
	io << "BitArray["
	each do |value|
	io << (value ? '1' : '0')
	end
	io << ']'
	end

It would be more convenient and make more sense to have the output format similar to Int.to_s - so that it can be converted from a base 2 digit into a number of a different base, i.e.

 def to_s(io : IO) : Nil 
   each do |value| 
     io << (value ? '1' : '0') 
   end 
 end 

If we want the string representation explicitly stated in the string, then we can use .inspect (keep the current implementation):

  def inspect(io : IO) : Nil
    io << "BitArray["
    to_s(io)
    io << ']'
  end

[asterite]

Even though I think it's a good idea to have a way to format it like that, I don't think the default should be that. If you see "1001" in the output of "to_s" you might think it's a number, when it's not.

[straight-shoota]

Providing an unambiguous representation is #inspect's job. #to_s is supposed to provide a natural representation. A series of 1 and 0 seems like a very natural representation to me. I'm not sure if that's definitely better for to_s, though. I don't think this type is used often for direct user presentation.
So maybe it could help if you could tell a bit about your use case, @dukeraphaelng?