Update doc text.

doc.go

@@ -25,9 +25,8 @@ request parameters using the UnmarshalParams method on the request:
 	}
 
 The handler package makes it easier to use functions that do not have this
-exact type signature as handlers, by using reflection to wrap other function
-types to satisfy the Handler signature.  For example, suppose we want to export
-this Add function:
+exact type signature as handlers, using reflection to wrap them in a Handler
+function.  For example, suppose we want to export this Add function:
 
 	// Add returns the sum of a slice of integers.
 	func Add(ctx context.Context, values []int) int {