The `then` keyword

Property definitions

	# The `then` keyword
	var n_kwthen: TKwthen is writable, noinit

src/parser/parser_nodes.nit:1990,2--1991,42

	redef fun n_kwthen=(node)
	do
		_n_kwthen = node
		node.parent = self
	end

src/parser/parser_prod.nit:3174,2--3178,4