PORT-AU-PRINCE, Haiti—Haitian President Jovenel Moïse announced Sunday that police have arrested more than 20 people he accused of trying to kill him and overthrow his government, including a Supreme Court judge who has the support of opposition leaders demanding that Moïse step down. Moïse spoke at Haiti’s airport in Port-au-Prince, flanked by the country’s prime minister and the police chief as he prepared to leave for the southern coastal town of Jacmel for the opening ceremony of its yearly carnival, which is being held amid the pandemic. “There was an attempt on my life,” he said. Moïse said the alleged plot began Nov. 20 but did not provide further details or any evidence except to say among the people arrested is a judge and an inspector general with the police. Meanwhile, Prime Minister Joseph Joute said authorities found several weapons and a speech that Supreme Court Judge Yvickel Dabrézil had …