Single Pole Light Switch 3 Black Wires
The wire wrapped around the screw and the wire "stabbed" into the port next to it are connected together internally within the switch.  With the switch off, test for voltage to determine if the lone wire, on the bottom of the switch, is the hot (line) or if the two connected wires, on the top, are together the hot (line).  The two wires currently connected together on your existing switch should be again connected together on your new switch.

Good Luck,
Volt-Ron