PETATLAN, Mexico Unidentified assailants lobbed a grenade inside a restaurant near Mexico's Pacific coast today, injuring about 40 people. Several people were celebrating the birthday of the local mayor's chauffeur when the incident happened in the town of Petatlan (peh-TAHT'-lahn), about 100 miles northwest of Acapulco. The mayor wasn't present. The attack is the second in three days along the Pacific coast. Late Monday night, assailants threw a grenade at a home in the resort city of Acapulco, wounding two men and three women. Acapulco Mayor Felix Salgado said the attack was carried out by members of an organized criminal...