Sixty-two years after leading a guerrilla army out of the mountain jungles of Cuba and helping his brother, Fidel Castro, impose communist rule over the island, Raúl Castro on Friday said he will relinquish his hold on formal power in the nation’s affairs. As has been widely expected, Raúl Castro, 89, said he was stepping down as head of the Cuban Communist Party, the island’s dominant political force, during a subdued opening session of the body’s Eighth Congress in Havana. In remarks during an address to delegates in Havana’s convention center, Raúl Castro announced he would not seek to reta...