Document netif API in doxygen module style

src/core/dns.c

@@ -60,6 +60,8 @@
  * must be implemented by the module that uses the resolver).
  * 
  * All functions must be called from TCPIP thread.
+ * 
+ * @see @ref netconn_dns
  */
 
 /*-----------------------------------------------------------------------------

src/core/tcp.c

@@ -40,7 +40,7 @@
  * @defgroup tcp_raw TCP
  * @ingroup raw_api
  * Transmission Control Protocol for IP\n
- * @see @ref raw_api
+ * @see @ref raw_api and @ref netconn
  *
  * Common functions for the TCP implementation, such as functinos
  * for manipulating the data structures and the TCP timer functions. TCP functions

src/core/udp.c

@@ -40,7 +40,7 @@
  * @defgroup udp_raw UDP
  * @ingroup raw_api
  * User Datagram Protocol module\n
- * @see @ref raw_api
+ * @see @ref raw_api and @ref netconn
  */
 
 /* udp.c