and for separation of concerns:
The final G-code preview no more uses ExtrusionPaths structure
to hold the G-code path data extracted by parsing the G-code.
Instead, the ExtrusionPath class has been trimmed down back to
the original size before the G-code preview was introduced,
and a new GCodePreviewData::Extrusion::Path class was created to hold
the additional path data as the extruder ID, color change ID
and fan speed.