Added example for toggling microphone

Author: AndreasArvidsson

docs/Customization/Examples/toggle_listening.md

@@ -0,0 +1,9 @@
+If you want to completely prevent Talon from listening so not even the wake up commands are active you can do that by setting the microphone.
+
+```talon
+key(f9):
+    sound.set_microphone("None")
+
+key(f10):
+    sound.set_microphone("System Default")
+```