code: function insertDecl(decl, i, newDecl) {
    var next = decl.next()
    var declAfter
    if (
      next &&
      next.type === 'comment' &&
      next.raws.before.indexOf('\n') === -1
    ) {
      declAfter = next
    } else {
      declAfter = decl
    }
    declAfter.after(newDecl)
  }
docs: 在后面插入新的属性，并保持注释在当前行