Tokyo stocks rebounded Tuesday on buybacks of technology shares after heavy losses, while investors were focused on the closely contested U.S. presidential election with voting set to start later in the day. The 225-issue Nikkei Stock Average ended up 421.23 points, or 1.11 percent, from Friday at 38,474.90. The broader Topix index finished 20.00 points, or 0.76 percent, higher at 2,664.26. Japanese financial markets were closed Monday for a national holiday. The Tokyo Stock Exchange extended its regular trading hours by 30 minutes from Tuesday to close on 3:30 p.m. as part of its efforts to m…