Link to pretty printer library.

README.md

@@ -104,8 +104,9 @@ putLText :: MonadIO m => TL.Text -> m ()
 
 Generally speaking writing manual instances of Show is a [Haskell antipattern](
 http://www.stephendiehl.com/posts/strings.html) because it produces
-law-violating instances of Show. You probably want to use a pretty printer
-library for custom printing.
+law-violating instances of Show. You probably want to use a [pretty
+printer](https://hackage.haskell.org/package/wl-pprint-text) library for custom
+printing.
 
 If backwards compatibility is needed then the base library can be imported
 manually.
@@ -114,6 +115,9 @@ manually.
 import GHC.Show (Show(..))
 ```
 
+Automatic deriving of ``Show`` for your types is still supported since the class
+is in scope by default.
+
 * **Partial functions like ``undefined`` and ``error`` raise compiler warnings on
   usage.**