fix up overapplication to file names

src/public_include/decaf/sha512.hxx

@@ -1,5 +1,5 @@
 /**
- * @file decaf/decaf_sha512.hxx
+ * @file decaf/sha512.hxx
  * @copyright
  *   Based on public domain code by Dan Bernstein \n
  *   Copyright (c) 2015 Cryptography Research, Inc.  \n

src/public_include/decaf/shake.hxx

@@ -1,5 +1,5 @@
 /**
- * @file decaf/decaf_shake.hxx
+ * @file decaf/shake.hxx
  * @copyright
  *   Based on CC0 code by David Leon Gil, 2015 \n
  *   Copyright (c) 2015 Cryptography Research, Inc.  \n

src/utils.c

@@ -3,7 +3,7 @@
  */
 
 /**
- * @file decaf_utils.c
+ * @file utils.c
  * @author Mike Hamburg
  * @brief Decaf utility functions.
  */