trying to capture bug references e.g. 'bug 314159' in a Google spreadsheet and convert it to a link

code.gs

function onEdit(e) {

//  https://code.google.com/p/google-apps-script-issues/issues/detail?id=2521
//  var e = { range: SpreadsheetApp.getActiveRange(), value : "bug 972929" };

  function fetchBug(bugNumber) {
    var url = "https://api-dev.bugzilla.mozilla.org/latest/bug/" + bugNumber;
    var parameters = {};
    var response = UrlFetchApp.fetch(url, parameters);
    var json = response.getContentText();
    var data = JSON.parse(json);
    return data;
  }

  var bugRegex = /bug\s(\d+)/;  
  // The presence of e.value indicates this is a single cell edit
  if (e && e.value && bugRegex.test(e.value)) {
    var bug = e.value.match(bugRegex)[1];
    var data = fetchBug(bug);
    var link = "https://bugzilla.mozilla.org/show_bug.cgi?id=" + data["id"];
    var title = "Bug " + data["id"] + " " + "(" + data["summary"] + ")";
    if (data['assigned_to'] && data['assigned_to']['name'] && data['assigned_to']['name'] != 'nobody') {
      e.range.setComment("Assigned To: " + data['assigned_to']['real_name']);      
    }
    e.range.setFormula("=HYPERLINK(\"" + link + "\", \"" + title + "\")");
  } else {
    Logger.log(e); 
  }
}