Fix warnings and generate docs

Author: ethul

docs/React.md

@@ -297,7 +297,7 @@ Read the component state.
 #### `transformState`
 
 ``` purescript
-transformState :: forall props state eff. ReactThis props state -> (state -> state) -> Eff (state :: ReactState ReadWrite | eff) state
+transformState :: forall props state eff. ReactThis props state -> (state -> state) -> Eff (state :: ReactState ReadWrite | eff) Unit
 ```
 
 Transform the component state by applying a function.

src/React.purs

@@ -61,7 +61,7 @@ module React
   , createFactory
   ) where
 
-import Prelude (Unit(), ($), bind, pure, return, unit)
+import Prelude (Unit(), pure, return, unit)
 
 import Control.Monad.Eff (Eff())