Improve pf_fuel_pos_replace() header
As pointed out in https://osdn.net/projects/freeciv/ticket/46136#comment:12505:46136:1669871392 , pf_fuel_pos_replace() documentation should be made clearer.
This seems more clear to my own eye, but not sure if others would feel the same way.
As pointed out in https://osdn.net/projects/freeciv/ticket/46136#comment:12505:46136:1669871392 , pf_fuel_pos_replace() documentation should be made clearer.