Feature request: Document how to use CsWin32 manually without the source generator

[MatejKafka]

I'd like to invoke CsWin32 manually in my project (that is, use the nuget package and invoke it from my code, passing it a generated list of functions to generate bindings for and getting back the generated source code). It seems that CsWin32 provides a public API, but it's not publicly documented and there are no examples of how to use it that I could find.

I mostly managed to figure it out by reading through the source code (https://github.com/MatejKafka/powershell-profile/blob/master/CustomModules/PSWin32/PSWin32.psm1), but imo there are other developers who might also be interested in using CsWin32 in this way.

It might not be worth it to write an official documentation given that this is probably a pretty niche scenario, but even publishing a few commented sample programs invoking Microsoft.Windows.CsWin32.Generator to illustrate how to call it would be very useful.