Add missing C# verification

[PathogenDavid]

• [ ] Ensure no ClangSharpTypereference are present anywhere in the entire tree
• [ ] Ensure no VoidTypeReference are present for fields, parameters, or underlying enum types. (Probably easier to check if they're allowed rather than when they're not.)
• [ ] Ensure all TranslatedTypeReference actually resolve https://github.com/InfectedLibraries/Biohazrd/issues/109
• [ ] Ensure TranslatedRecord.Members doesn't have any unexpected declarations.
• [ ] Ensure TranslatedVTableField.Accessibility is <= TranslatedVTable.Accessibility
• [ ] Ensure the relevant entries of a vTable were not moved or removed. (VTables are translated with sequential layout so this breaks the vTable. Adding to the end should be OK though.) (Requires https://github.com/InfectedLibraries/Biohazrd/issues/112)
• [ ] Verify that implicit values of enums are contiguous
  • Right now this is being done at output generation time.
• [ ] Verify all identifiers are legal in C#. (We handle by replacing the illegal characters with obnoxiously long __UNICODE_0123__, so this should only be a warning. See CSharpCodeWriter.IsLegalIdentifier)

[PathogenDavid]

I've marked this with the relatively small label. Each one of these is small on its own, not the entire issue.