update docs

keyboards/handwired/promethium/readme.md

@@ -5,8 +5,9 @@ A handwired Planck based keyboard using the Adafruit Feather 32u4 Bluefruit LE c
 Features:
 
 * Single piece split form factor
-* Vertical staggered
+* Columnar stagger
 * Trackpoint
 * Bluetooth LE *TBD*
 * Battery
-* Per switch RGB LED
+* Per switch RGB LED
+* Proximity sensor for energy conservation *TBD*