RazorProjectExtensions.GetSourceGeneratedDocumentsForGeneratorAsync should only consider the path and generator name

[chsienki]

RazorProjectExtensions.GetSourceGeneratedDocumentsForGeneratorAsync constructs the entire generator identity before comparing. This has issues with path matching though as it considers the paths in a case-sensitive way. The assembly mapping logic in Roslyn uses the path returned by the VSIX apis which upper cases a large portion of the assembly path, meaning the identities don't match when Roslyn loads the razor generator first.

Instead of taking the entire identity we should just consider the path and name of the generator. When considering the path we should do it in a platform correct manor (i.e. case insensitive on windows)