OdbcConnection.ServerVersion may return null but docs says it will throw or return "" instead

[krwq]

See docs: https://docs.microsoft.com/en-us/dotnet/api/system.data.odbc.odbcconnection.serverversion?view=dotnet-plat-ext-3.1

but implementation OdbcConnectionOpen.ServerVersion will return null in some cases.

Either docs or implementation should be fixed here.

Found when applying nullable annotations

[ghost]

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[roji]

Yeah, I ran across this during annotation: https://github.com/dotnet/runtime/blob/master/src/libraries/System.Data.Odbc/src/System/Data/Odbc/OdbcConnectionOpen.cs#L35 (based on #689).

[krwq]

Yes, this is based on your comment, I'll be removing TODO-NULLABLEs or replacing them with issues or fixing in a PR soon