Add comments about raw mode

Author: Anton-4

examples/tty.roc

@@ -3,6 +3,9 @@ app [main!] { pf: platform "../platform/main.roc" }
 import pf.Stdout
 import pf.Tty
 
+## Raw mode allows you to change the behaviour of the terminal.
+## This is useful for running an app like vim or a game in the terminal.
+
 main! = |_args| {
     Stdout.line!("Tty: enabling raw mode")
     Tty.enable_raw_mode!()