Support commentable nodes

[enikao]

Does LionCore support commentable nodes out-of-the-box?
Do we need support on M3 level?

Assumptions:

• In any case will not influence M3 heavily

Decision: Postponed

[slisson]

MPS has separate operations for accessing the children with (.childrenAndAttributes<...>) and without (.children<...>) the commented ones. It's easy to pick the wrong one and forget to include the commented ones. Maybe we can make our API less error prone by adding support for them from the beginning and not add it later as it was done in MPS.

[markusvoelter]

Good point: while the storage and representation of commented nodes is not relevant to M3, the API is. In that sense this is something we should consider when defining M3 APIs.

[enikao]

MPS can only use sNodeAttributes to store commented nodes as it internally stores all children of a node in one list, and thus can move a commented child from its original link to the sNodeAttribute link and retain the child's position (according to Sergej).

Depending on #37, this solution might not work for us.

[enikao]

Briefly discussed on 2022-11-25, but couldn't come up with a good idea => postponed.