Update i3pystatus.rst

docs/i3pystatus.rst

@@ -1,6 +1,18 @@
 Module reference
 ================
 
+.. Don't list *every* module here, e.g. cpu-usage suffices, because the other
+    variants are listed below that one.
+
+:System: `clock`_ - `disk`_ - `load`_ - `mem`_  - `cpu-usage`_
+:Audio: `alsa`_ - `pulseaudio`_
+:Hardware: `battery`_ - `backlight`_ - `temp`_
+:Network: `network`_ - `wireless`_
+:Music: `now-playing`_ - `mpd`_
+:Websites & stuff: `weather`_ - `bitcoin`_ - `reddit`_ - `parcel`_
+:Other: `mail`_ - `pyload`_ -  `text`_ 
+:Advanced: `file`_ - `regex`_ - `runwatch`_ - `shell`_
+
 .. autogen:: i3pystatus Module
 
     .. note:: List of all modules: