Update adafruit_thermal_printer/thermal_printer_2168.py

Co-authored-by: Scott Shawcroft <scott@tannewt.org>

Author: greg-elmi

adafruit_thermal_printer/thermal_printer_2168.py

@@ -29,7 +29,7 @@
 versions and care must be taken to select the appropriate module inside this
 package for your firmware printer:
 
-* thermal_printer_2164 = Printers with firmware version 2.168+.
+* thermal_printer_2168 = Printers with firmware version 2.168+.
 * thermal_printer = The latest printers with firmware version 2.68 up to 2.168
 * thermal_printer_264 = Printers with firmware version 2.64 up to 2.68.
 * thermal_printer_legacy = Printers with firmware version before 2.64.