Extension modules - update MSVC for standalone module

The page https://devguide.python.org/developer-workflow/extension-modules/#updating-msvc-project-files has recently been updated with fantastic content.

However, it currently only shows how to add a built-in module for Windows, and not a separate extension module.

We should add a second section that adds a new .vcxproj for the new extension module (or more likely copies a recommended existing one), along with the other changes necessary to ensure the new module is correctly built and distributed.

从 issue 中链接的开发者工作流页面的“Updating MSVC project files”部分开始。记录为独立扩展模块创建或复制 .vcxproj 的其他步骤，包括构建和分发方面的更改；当页面涵盖内置扩展模块和独立扩展模块时即完成。