Added C# 9 record handling

[bigtlb]

C# 9 record type should work similar to class but it has some built in members and a specific inheritance, which may be better off hidden.

• Added a test for IsRecord And TypeKind.Record updated generation code to output record in place of class, but also consider record inn most places where classes are considered (although it can't inherit).
• Added in a helper method to determine if a member of a record is one of the builtin methods (Clone, ToString, Deconstruct, Equals, etc.).
• Also cleaned up blocks with unnecesary elses

  if (...)
  return;
  else if (...)
  return;
  else if (...)
  return;

  can be

  if (...)
  return;
  if (...)
  return;
  if (...)
  return;

Suggested next steps is hide IEquatable<T> inheritance and builtin members.

[ejball]

Thanks for the contribution! I agree that hiding IEquatable<T> and the synthesized members makes sense, except for the public properties.

[bigtlb]

Please advise on how I can make the build succeed.

[ejball]

Looks like XML documentation comments didn't work correctly with records under 5.0.100. I've changed GitHub Actions to use the latest .NET 5 SDK; perhaps merging that in that will fix the PR build.

[ejball]

You should also run .\build.ps1 generate-docs and commit those changes.

[bigtlb]

Thanks. I was just noticing that part.

[bigtlb]

Should be good now. it build on my branch.

[ejball]

Rebased and amended: #121. Thanks again!