code: function focusToCell(sq, range, targetCell) {
    range.selectNodeContents(targetCell);
    range.collapse(true);
    sq.setSelection(range);
  }
docs: Focus to cell.
  @param {squireext} sq - squire instance
  @param {range} range - range object
  @param {HTMLElement} targetCell - cell element for focus
  @ignore