Photo by dullshick Attention, Columbia Heights! The official word has just come down that D.C. Mayor Adrian Fenty will formally dedicate the new Columbia Heights Plaza and “Resonance” Fountain on Monday, Sept. 28 at 10:30 a.m. So let all the endless speculation cease. It does seem, however, that the plaza itself was pretty much mostly done and open last night. Also planned to be in attendance on Monday morning: Ward 1 Council member Jim…