Rework docs to use polyglot notebooks

Since fsdocs now supports generation of documentation with notebooks as input, a rework of the docs that also offers side-by-side examples for F# and C# is overdue.

I think this should be done gradually with a mechanism that allows publishing the new and old docs together as long as not all pages are ported.

This also would be a huge step forward for #376 , at least in a way that we could provide the docs in a format that is needed for the official pipeline.

首先查看 fsdocs 对基于 notebook 的文档的支持以及 issue #376 中的要求。确定如何在逐步迁移期间同时发布新旧文档，然后定义并列展示 F# 和 C# 示例的范围以及官方 pipeline 格式。