希望给密文变量增加 description 可选位

Describe the feature Features description

目前密文变量只有变量名和值，没有描述项：

希望给其增加 description ，参考 HuggingFace 的做法，见下图：

Motivation A clear and concise description of the motivation of the feature. Ex1. It is inconvenient when [....]. Ex2. There is a recent paper [....], which is very helpful for [....].

Related resources If there is an official code release or third-party implementations, please also provide the information here, which would be very helpful.

Additional context Add any other context or screenshots about the feature request here. If you would like to implement the feature and create a PR, please leave a comment here and that would be much appreciated.