docs: Add missing value in example (#37)

Fix print statement in example to actually include the combined error
object.

error.go

diff --git a/error.go b/error.go
index 04eb961..5c9b67d 100644
--- a/error.go
+++ b/error.go
@@ -54,7 +54,7 @@
 //
 // 	errors := multierr.Errors(err)
 // 	if len(errors) > 0 {
-// 		fmt.Println("The following errors occurred:")
+// 		fmt.Println("The following errors occurred:", errors)
 // 	}
 //
 // Advanced Usage