Added submodule contents into tree

externals/mbedtls/doxygen/input/doc_mainpage.h

@@ -0,0 +1,19 @@
+/**
+ * \file doc_mainpage.h
+ *
+ * \brief Main page documentation file.
+ */
+/*
+ *
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+/**
+ * @mainpage Mbed TLS v3.5.2 API Documentation
+ *
+ * This documentation describes the internal structure of Mbed TLS.  It was
+ * automatically generated from specially formatted comment blocks in
+ * Mbed TLS's source code using Doxygen.  (See
+ * https://www.doxygen.nl for more information on Doxygen)
+ */