INDIANAPOLIS — Ghoulish gawkers are turning the scene of Mark Sanchez’s stabbing into one of Indianapolis’ hottest new tourist attractions. Passersby have been stopping and taking pictures at the stretch of downtown sidewalk where Sanchez limped after being knifed around midnight Saturday. The trail of blood was still spattered up the sidewalk and into the alley on Monday after the ex Jets quarterback allegedly bashed a grease truck driver. “It sounds like he deserved it,” a woman said to her