Fix nbtty comment

Author: fhunleth

rootfs_overlay/etc/erlinit.config

@@ -13,9 +13,7 @@
 # wrong one.
 --warn-unused-tty
 
-# Use dtach to capture the iex session so that it can be redirected to the
-# app's GUI
-#-s "/usr/bin/dtach -N /tmp/iex_prompt"
+# Use nbtty to improve terminal handling on serial ports. It's a noop on HDMI.
 -s "/usr/bin/nbtty"
 
 # Specify the user and group IDs for the Erlang VM