At least two more suspects have now been arrested in the Aug. 18 slaying of a pizza restaurant owner in the Edgewood neighborhood, WTOP’s Mark Segraves reports. One suspect, Shanika Robinson, had already been arrested in the killing of Pizza Mart co-owner Shahabuddin Rana a few weeks ago, but now her brother, Leon Robinson, has also been taken into custody and charged with first degree murder. Segraves also tells DCist that a third suspect, whose…