Name of a resource found in the res/drawable-* folders to use for the small icon

By default, we use the app's icon, named "icon". A valid icon must be used to display notifications.

Property definitions

android $ Notification :: _small_icon
	# Name of a resource found in the `res/drawable-*` folders to use for the small icon
	#
	# By default, we use the app's icon, named "icon". A valid icon must be used
	# to display notifications.
	var small_icon: nullable Text = null is writable
lib/android/notification/notification.nit:52,2--56,49