As I mentioned last week, the PBS show NewsHour with Jim Lehrer is in town this week for a "City Spotlight" feature on St. Louis.Tonight correspondent Gwen Ifill hosts a forum discussing downtown St. Louis gentrification. Tomorrow she leads a "town hall" meeting on President Barack Obama's first 100 days in office. What I didn't note last week was that apparently the NewsHour crew also plans to provide arts coverage of St. Louis. Per the show's art blog, they've already checked out a Chuck Berry