Update Copyright headers

src/hb-ot-tag.h

diff --git a/src/hb-ot-tag.h b/src/hb-ot-tag.h
index 345c80e..427a069 100644
--- a/src/hb-ot-tag.h
+++ b/src/hb-ot-tag.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009  Red Hat, Inc.
+ * Copyright © 2009  Red Hat, Inc.
  *
  *  This is part of HarfBuzz, a text shaping library.
  *