Mark Schilling Japan CorrespondentKosugi Yoshinobu, the president of the Nippon TV network, issued a public apology on Monday for a slur used by a comedian on the NTV infotainment show “Sukkiri” on March 12.The comic was commenting on a documentary that spotlighted a woman belonging to the Ainu, an indigenous people that live primarily on the northern island of Hokkaido and have long been the targets of discrimination by the majority Japanese.At the start of a regularly scheduled press