Clarify that the transitionLanes used by Transition Tracing is a LaneMap (#32800)

We have a high level concept for this used elsewhere.

We should use this for `transitionTypes` too:


https://github.com/facebook/react/blob/main/packages/react-reconciler/src/ReactInternalTypes.js#L285

As mentioned in #32797 we could also just use the `transitionLanes`
since the `types` are also on the `Transition` objects. If we always
stored this set.