Bug: Tooling P/Invoke declarations conflicts with source generations in end-user projects

[Lamparter]

Related: Lamparter/Win32#2
Related: microsoft/CsWin32#1312

Description

The PInvoke class from Riverside.Tooling.CsWin32 will conflict with the PInvoke class in the end user project.

Steps to reproduce

1. Open a project
2. Add any Cubekit project as a dependency
3. Use CsWin32 in that project
4. See an error when using PInvoke

Version

2.0.0-rc3

[Lamparter]

I think it's possible to customise the namespace that the generations are included in, that's probably what should be done here