Update Doxygen file blocks to remove copyright and license information
diff --git a/include/mbedtls/bignum.h b/include/mbedtls/bignum.h
index 0b40015..c20b367 100644
--- a/include/mbedtls/bignum.h
+++ b/include/mbedtls/bignum.h
@@ -1,8 +1,9 @@
 /**
  * \file bignum.h
  *
- * \brief  Multi-precision integer library
- *
+ * \brief Multi-precision integer library
+ */
+/*
  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
  *  SPDX-License-Identifier: Apache-2.0
  *