Enum PageNavigationType

// Create a form and add a new multiple-choice item and a page-break item.
var form = FormApp.create('Form Name');
var item = form.addMultipleChoiceItem();
var pageBreak = form.addPageBreakItem();

// Set some choices with go-to-page logic.
var rightChoice = item.createChoice('Vanilla', FormApp.PageNavigationType.SUBMIT);
var wrongChoice = item.createChoice('Chocolate', FormApp.PageNavigationType.RESTART);

// For GO_TO_PAGE, just pass in the page break item. For CONTINUE (normally the default), pass in
// CONTINUE explicitly because page navigation cannot be mixed with non-navigation choices.
var iffyChoice = item.createChoice('Peanut', pageBreak);
var otherChoice = item.createChoice('Strawberry', FormApp.PageNavigationType.CONTINUE);
item.setChoices([rightChoice, wrongChoice, iffyChoice, otherChoice]);