Add parens around arrow functions

This allows the examples to parse, and not SyntaxError

Author: littledan

README.md

@@ -64,8 +64,8 @@ let person = { score: 25 };
 
 let newScore = person.score
   |> double
-  |> _ => add(7, _)
-  |> _ => boundScore(0, 100, _);
+  |> (_ => add(7, _))
+  |> (_ => boundScore(0, 100, _));
 
 newScore //=> 57