added buttons

parts_list.md

@@ -2,7 +2,7 @@
 - Raspberry Pi Pico W [(3996082)](https://fi.farnell.com/en-FI/raspberry-pi/raspberry-pi-pico-w/mcu-board-rpi-pico-w-264kb-133mhz/dp/3996082)
 - 7-Segment Display [(1003273)](https://fi.farnell.com/en-FI/broadcom-limited/hdsp-7501/led-display-0-3-he-red/dp/1003273)
 - 8 100Ω-resistors [(3541676)](https://fi.farnell.com/en-FI/koa-speer-electronics/mos1-2ct52r101j/res-100r-0-5w-axial-metal-oxide/dp/3541676)
-- 3 Buttons 
+- 3 Buttons [(1634621)](https://fi.farnell.com/multicomp-pro/r13-502a-05-r/switch-spst-3a-125v-solder-red/dp/1634621)
 - 1 Latching Button/Switch [(674345)](https://fi.farnell.com/en-FI/eoz/09-03290-01/switch-spdt-co-0-5a-12v-pcb-black/dp/674345)
 - 1 Schottky Diode [(9801197)](https://fi.farnell.com/en-FI/stmicroelectronics/1n5817/diode-schottky-1a-20v-do-41/dp/9801197)
 - 1 Battery Holdeer [(1702630)](https://fi.farnell.com/keystone/2462/battery-holder/dp/1702630)