add `Description :` field for haddock

descriptions are copied from README mostly, but a couple
were missing from there

IHaskell/Completion.hs

 {-# LANGUAGE PatternGuards #-}
-{- | very approximate completion. Seems to generate what is required by
+{- | Description : generates tab-completion options
+
+ very approximate completion. Seems to generate what is required by
  <http://ipython.org/ipython-doc/dev/development/messaging.html#complete>,
  but for whatever reason nothing gets added when the liftIO below prints
  stuff like:

IHaskell/Config.hs

 {-# LANGUAGE QuasiQuotes #-}
+-- | Description : IPython configuration files are compiled-into IHaskell
 module IHaskell.Config (ipython, notebook, console, qtconsole, customjs) where
 
 import Data.String.Here

IHaskell/Eval/Evaluate.hs

 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE NoImplicitPrelude #-}
--- | This module exports all functions used for evaluation of IHaskell input.
+{- | Description : Wrapper around GHC API, exposing a single `evaluate` interface that runs
+                   a statement, declaration, import, or directive.
+
+This module exports all functions used for evaluation of IHaskell input.
+-}
 module IHaskell.Eval.Evaluate (
   interpret, evaluate, Interpreter, liftIO
   ) where

IHaskell/IPython.hs

+-- | Description : Shell scripting wrapper using @Shelly@ for the @notebook@, @setup@, and
+--                 @console@ commands.
 module IHaskell.IPython (
   runIHaskell,
   setupIPythonProfile,

IHaskell/Message/Parser.hs

 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE NoImplicitPrelude #-}
--- | This module is responsible for converting from low-level ByteStrings
--- | obtained from the 0MQ sockets into Messages. The only exposed function is
--- | `parseMessage`, which should only be used in the low-level 0MQ interface.
+-- | Description : Parsing messages received from IPython
+--
+-- This module is responsible for converting from low-level ByteStrings
+-- obtained from the 0MQ sockets into Messages. The only exposed function is
+-- `parseMessage`, which should only be used in the low-level 0MQ interface.
 module IHaskell.Message.Parser (parseMessage) where
 
 import ClassyPrelude

IHaskell/Message/UUID.hs

--- | Generate, parse, and pretty print UUIDs for use with IPython.
+-- | Description : UUID generator and data structure
+--
+-- Generate, parse, and pretty print UUIDs for use with IPython.
 module IHaskell.Message.UUID (
   UUID,
   random, randoms,

IHaskell/Message/Writer.hs

 {-# LANGUAGE CPP #-}
--- | This module contains the @ToJSON@ instance for @Message@.
+-- | Description : @ToJSON@ for Messages
+--
+-- This module contains the @ToJSON@ instance for @Message@.
 module IHaskell.Message.Writer (
   ToJSON(..)
 )  where

IHaskell/Types.hs

 {-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE OverloadedStrings #-}
+-- | Description : All message type definitions.
 module IHaskell.Types (
   Profile (..),
   Message (..),

IHaskell/ZeroMQ.hs

--- | The "ZeroMQ" module abstracts away the low-level 0MQ based interface with IPython,
+-- | Description : Low-level ZeroMQ communication wrapper.
+--
+-- The "ZeroMQ" module abstracts away the low-level 0MQ based interface with IPython,
 -- replacing it instead with a Haskell Channel based interface. The `serveProfile` function
 -- takes a IPython profile specification and returns the channel interface to use.
 module IHaskell.ZeroMQ (

Main.hs

 {-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE OverloadedStrings #-}
+-- | Description : Argument parsing and basic messaging loop, using Haskell
+--                 Chans to communicate with the ZeroMQ sockets. 
+module Main where
 import ClassyPrelude hiding (liftIO)
 import Control.Concurrent.Chan
 import Data.Aeson