Warnings for Invalid Metadata are Reported on Incorrect Lines

[InsertCreativityHere]

I was fixing some of our errorDetection tests and noticed that the line number are off. For example, take WarningInvalidMetaData.ice

In the source we have: https://github.com/zeroc-ice/ice/blob/60c41eab191ebdc522ac402ff4e0ec96f3c9351a/cpp/test/Slice/errorDetection/WarningInvalidMetaData.ice#L55-L59 But in the expected errors: https://github.com/zeroc-ice/ice/blob/60c41eab191ebdc522ac402ff4e0ec96f3c9351a/cpp/test/Slice/errorDetection/WarningInvalidMetaData.err#L18-L20

You will notice that 56 != 58.