The designator children describes any direct child of the current note.
This change removes the contextual ambiguity of 'child' between group and item scope usage. The 'child' designator is now assumed to only be for item scope.
As designators ignore map adornments, a container note with just adornments on it but child notes with evaluate as having a $ChildCount (the number of adornments) but no 'children' (the number of notes).