Append: Fix name in example (#25)
The example was using Combine instead of Append.
diff --git a/error.go b/error.go
index de6ce47..150fd95 100644
--- a/error.go
+++ b/error.go
@@ -33,7 +33,7 @@
// If only two errors are being combined, the Append function may be used
// instead.
//
-// err = multierr.Combine(reader.Close(), writer.Close())
+// err = multierr.Append(reader.Close(), writer.Close())
//
// This makes it possible to record resource cleanup failures from deferred
// blocks with the help of named return values.
