updateLineEndingMenu (windowId, lineEnding) {
    const menus = this.getWindowMenuById(windowId)
    const crlfMenu = menus.getMenuItemById('crlfLineEndingMenuEntry')
    const lfMenu = menus.getMenuItemById('lfLineEndingMenuEntry')
    if (lineEnding === 'crlf') {
      crlfMenu.checked = true
    } else {
      lfMenu.checked = true
    }
  }
Update line ending menu items.

@param {number} windowId The window id.
@param {string} lineEnding Either >lf< or >crlf<.