add preamble text to each service-providing-module

modules/hostapd/default.nix

@@ -1,3 +1,16 @@
+## Hostapd
+## =======
+##
+## Hostapd (host access point daemon) enables a wireless network
+## interface to act as an access point and authentication server,
+## providing IEEE 802.11 access point management, and IEEE
+## 802.1X/WPA/WPA2/EAP Authenticators. In less technical terms,
+## this service is what you need for your Liminix device to
+## provide a wireless network that clients can connect to.
+##
+## If you have more than one wireless network interface (e.g.
+## wlan0, wlan1) you can run an instance of hostapd on each of them.
+
 { lib, pkgs, config, ...}:
 let
   inherit (lib) mkOption types;