Various fixes to doxygen API generation

 * Fixed incorrect file definitions
 * Fixed accidental tag problems in ecjpake.h
 * Corrected function naming in X.509 module definition
diff --git a/include/mbedtls/sha256.h b/include/mbedtls/sha256.h
index bc8b226..f8041ad 100644
--- a/include/mbedtls/sha256.h
+++ b/include/mbedtls/sha256.h
@@ -1,5 +1,5 @@
 /**
- * \file mbedtls_sha256.h
+ * \file sha256.h
  *
  * \brief SHA-224 and SHA-256 cryptographic hash function
  *