Marchers and police clashed on Friday night toward the end of the Trans March in San Francisco’s Tenderloin, according to multiple witnesses and footage of the skirmish. Three witnesses told the Chronicle it all started when police tried to arrest someone spray painting a building on Market Street. When marchers approached and tried to block the arrest, officers responded with force, according to Nora Long and other witnesses. People could be heard on video shared with the Chronicle, repeatedly yelling, “let him go.” there trying to stop them,” Long told the Chronicle. “From there, the cops responded with more violence.”...