The boolean operand of the `not`

Property definitions

	# The boolean operand of the `not`
	var n_expr: AExpr is writable, noinit

src/parser/parser_nodes.nit:2211,2--2212,38

	redef fun n_expr=(node)
	do
		_n_expr = node
		node.parent = self
	end

src/parser/parser_prod.nit:3951,2--3955,4