PluralLocalizationFormatter doesn't support ushort/uint/ulong

[0x15e]

This should be easily fixable by adding those to the check at PluralLocalizationFormatter.cs:56.

Let me know if you want a pull request for it.

[axunonb]

@0x15e: Absolutely, highly appreciated.
My plan was a new release during next few days, so it would be great to have this included.