Add keypress instruction at end of summary

setup/so-whiptail

@@ -616,6 +616,9 @@ whiptail_end_settings() {
 		fi
 	fi
 
+	__append_end_msg ""
+	__append_end_msg "Press TAB to select yes or no."
+
 	whiptail --title "The following options have been set, would you like to proceed?" --yesno "$end_msg" 24 75 --scrolltext
 
 	local exitstatus=$?