Wall Street Journal: With sales of hybrid vehicles sinking, a green-advertising battle is erupting between Toyota Motor’s new Prius and Honda Motor’s new Insight. Beginning today, Toyota, the world’s largest auto maker, is rolling out a major U.S. ad push for its 2010 Prius, the third generation of the world’s top-selling hybrid vehicle. The car hits dealerships in the coming weeks. The Prius television ads — heavy on the special effects — feature a utopian landscape made entirely of people; the …