Every proposal for legislation which is to be submitted to the voters for their approval or for an expression of their opinion including, without limitation because of enumeration, proposed constitutional amendments, advisory referenda, and legislation designed to become effective only after ratification by the voters shall include a complete statement of the referendum question upon which the voters shall be requested to vote in the form prescribed under s. 5.64 (2). No such proposal shall be passed by either house of the legislature unless it contains the precise wording of the referendum question which is to be submitted to the voters for their approval, expression of opinion or ratification.