Rents are rising again across the country, squeezing tenants who are already coping with high gasoline prices and improving returns to landlords after a deep five-year slump. The turnaround appears to be another sign that the boom in house prices and sales is finally slowing, as homes have become so expensive in many metropolitan areas that some people have decided to rent instead. A government report yesterday also offered new evidence that the housing boom could be reaching a peak. The median price of a newly built home fell to $203,800 in July from $219,500 in June, after having risen...