Add [Flags] to RVOLayer

[ffbh]

when I use & operator for two RVOLayer variable, Bitwise operation on enum is not marked by [Flags] attribute from Rider
and the Debug.Log will out the specific RVOLayers the variable has instead of only showing a int value for multiply RVOLayer

[aron_granberg]

Hi

Unity has this annoying behavior that it will show all enums with that attribute as mask fields. But often I do not want it to show up as a mask field. I don’t think it’s possible to disable this default behavior…

In fact, there’s even a comment on the RVOLayer enum: