Change `UndoSculpt` to `StepData` and `usculpt` to `step-data`. Previously it wasn't clear that the struct contained the data for a single undo step and wasn't some more general thing.
Change `UndoSculpt` to `StepData` and `usculpt` to `step-data`. Previously it wasn't clear that the struct contained the data for a single undo step and wasn't some more general thing.