Made diesel render as brown in vehicle ui, fixing all resources

colours after gasoline, including water, fixes #9727
I'm pretty sure this for block is responsible for printing the fuel usage of the engines, like (Fuel Usage 4, 1, 5) where each number is in the proper resource colour for gasoline etc. I think this should fit at least 8 types of fuels before breaking.
The code your thinking of is called underneath the for loop, at veh->print_fuel_indicator, looks like I should add a check to that as you say.