Merge pull request #1692 from arduino/Hannes7eicher/RX_TX_Docs_Fix

Update cheat-sheet.md

Author: Hannes7eicher

content/hardware/02.hero/boards/uno-r4-minima/tutorials/cheat-sheet/cheat-sheet.md

@@ -209,10 +209,10 @@ The reference voltage of all digital pins is 5 V.
 The UNO R4 Minima has a total of four LEDs, three of which are programmable:
 - **ON** - power LED, cannot be programmed.
 - `LED_BUILTIN` - classic "built-in LED", attached to pin 13.
-- `RX_LED` - LED labelled "RX" on the board.
-- `TX_LED` - LED labelled "TX" on the board.
+- `LED_RX` - LED labelled "RX" on the board.
+- `LED_TX` - LED labelled "TX" on the board.
 
-To control these, define them as outputs and write desired state. The below example blinks each LED every second.
+To control these, define them as outputs and write the desired state. The below example blinks each LED every second.
 
 ```arduino
 void setup(){