Fix minor typos (#40)

Author: NickShadder

src/main/scala/shapeless/HListExercises.scala

@@ -143,13 +143,13 @@ object HListExercises extends FlatSpec with Matchers with org.scalaexercises.def
     apap.toList should be(res0)
 
   /** And it has a `Typeable` type class instance (see below), allowing, eg. vanilla `List[Any]`'s or `HList`'s with
-   * elements of type `Any` to be safely cast to precisely typed `HList`'s.
-   * These last three features make this `HList` dramatically more practically useful than `HList`'s are typically thought to be:
-   * normally the full type information required to work with them is too fragile to cross subtyping or I/O boundaries.
-   * This implementation supports the discarding of precise information where necessary.
-   * (eg. to serialize a precisely typed record after construction), and its later reconstruction.
-   * (eg. a weakly typed deserialized record with a known schema can have it's precise typing reestabilished).
-   */
+    * elements of type `Any` to be safely cast to precisely typed `HList`'s.
+    * These last three features make this `HList` dramatically more practically useful than `HList`'s are typically thought to be:
+    * normally the full type information required to work with them is too fragile to cross subtyping or I/O boundaries.
+    * This implementation supports the discarding of precise information where necessary.
+    * (eg. to serialize a precisely typed record after construction), and its later reconstruction.
+    * (eg. a weakly typed deserialized record with a known schema can have its precise typing reestablished).
+    */
   def exerciseTypeable(res0: Option[APAP]) = {
     import syntax.typeable._