Being a news anchor at a time of cratering trust in the media has its challenges. Like having Trump-ian insults hurled at you on social media — or a New York City sidewalk. But Lester Holt is fully committed to the at-times-Sisyphean-task of changing hearts and minds. “We’re going to have to just keep pushing forward, and being good,” he says. Pushing forward is something of a trademark for Holt, who has been “Nightly News” anchor and managing editor since 2015 and helmed “Dateline” since 2011. In fact, Holt’s unyielding work ethic is legendary at NBC News, where his typically marathon stretches on the anchor desk during breaking news earned him the sobriquet “Iron Pants.” Today, he’s still in the office most days in time for the 9:30 a.m. news meeting and may not leave until 10 p.m., if the West Coast feed of “Nightly” needs updating. During the pandemic, he started a weekly digital “Nightly” newscast for kids, and also began to write and deliver periodic essays on “Nightly News.” He