Update README.md

fir "h3" for responders

README.md

@@ -23,7 +23,7 @@ Follow these steps to load the initiator and responder firmware on the DWM1001-D
 
 3. Open the project in Segger, set the device ID to the desired value, connect the target device via USB and click Build and Run.
 
-# Responders
+### Responders
 1. Copy the folder dwm1001-examples/examples/ss_twr_init and change the name to ss_twr_resp to identify it.
 
 2. Replace the files ss_init_main.c and main.c with the ones of the same name provided in the folder Responder (inside of the Autocalibration or Localization folder depending on your objective).