Change header comment

src/hb-unicode.c

diff --git a/src/hb-unicode.c b/src/hb-unicode.c
index a897f23..e155d6d 100644
--- a/src/hb-unicode.c
+++ b/src/hb-unicode.c
@@ -1,7 +1,7 @@
 /*
  * Copyright (C) 2009  Red Hat, Inc.
  *
- *  This is part of HarfBuzz, an OpenType Layout engine library.
+ *  This is part of HarfBuzz, a text shaping library.
  *
  * Permission is hereby granted, without written agreement and without
  * license or royalty fees, to use, copy, modify, and distribute this