The `null` keyword

Property definitions

	# The `null` keyword
	var n_kwnull: TKwnull is writable, noinit

src/parser/parser_nodes.nit:2764,2--2765,42

	redef fun n_kwnull=(node)
	do
		_n_kwnull = node
		node.parent = self
	end

src/parser/parser_prod.nit:7168,2--7172,4