Fix and simplify newlines in doxygen documentation

Replace '\n' with '<br>', as this allows doxygen to understand reference
names followed by newline. For some cases just drop the newline if it's
not required.

Doxygen 1.8.15 doesn't like if the name of reference is followed by
anything else than (selected?) punctuation or whitespace.

bug #56004

src/core/altcp_alloc.c

@@ -1,6 +1,6 @@
 /**
  * @file
- * Application layered TCP connection API (to be used from TCPIP thread)\n
+ * Application layered TCP connection API (to be used from TCPIP thread)<br>
  * This interface mimics the tcp callback API to the application while preventing
  * direct linking (much like virtual functions).
  * This way, an application can make use of other application layer protocols

src/core/altcp_tcp.c

@@ -1,6 +1,7 @@
 /**
  * @file
- * Application layered TCP connection API (to be used from TCPIP thread)\n
+ * Application layered TCP connection API (to be used from TCPIP thread)
+ *
  * This interface mimics the tcp callback API to the application while preventing
  * direct linking (much like virtual functions).
  * This way, an application can make use of other application layer protocols

src/core/inet_chksum.c

@@ -1,6 +1,6 @@
 /**
  * @file
- * Internet checksum functions.\n
+ * Internet checksum functions.
  *
  * These are some reference implementations of the checksum algorithm, with the
  * aim of being simple, correct and fully portable. Checksumming is the

src/core/ipv6/dhcp6.c

@@ -16,8 +16,8 @@
  * - only start requests if a valid local address is available on the netif
  * - only start information requests if required (not for every RA)
  *
- * dhcp6_enable_stateful() enables stateful DHCPv6 for a netif (stateless disabled)\n
- * dhcp6_enable_stateless() enables stateless DHCPv6 for a netif (stateful disabled)\n
+ * dhcp6_enable_stateful() enables stateful DHCPv6 for a netif (stateless disabled)<br>
+ * dhcp6_enable_stateless() enables stateless DHCPv6 for a netif (stateful disabled)<br>
  * dhcp6_disable() disable DHCPv6 for a netif
  *
  * When enabled, requests are only issued after receipt of RA with the
@@ -453,14 +453,14 @@ dhcp6_information_request(struct netif *netif, struct dhcp6 *dhcp6)
 {
   const u16_t requested_options[] = {
 #if LWIP_DHCP6_PROVIDE_DNS_SERVERS
-    DHCP6_OPTION_DNS_SERVERS, 
+    DHCP6_OPTION_DNS_SERVERS,
     DHCP6_OPTION_DOMAIN_LIST
 #endif
 #if LWIP_DHCP6_GET_NTP_SRV
     , DHCP6_OPTION_SNTP_SERVERS
 #endif
   };
-  
+
   u16_t msecs;
   struct pbuf *p_out;
   u16_t options_out_len;

src/core/ipv6/mld6.c

@@ -5,12 +5,12 @@
  * @defgroup mld6 MLD6
  * @ingroup ip6
  * Multicast listener discovery for IPv6. Aims to be compliant with RFC 2710.
- * No support for MLDv2.\n
+ * No support for MLDv2.<br>
  * Note: The allnodes (ff01::1, ff02::1) group is assumed be received by your
  * netif since it must always be received for correct IPv6 operation (e.g. SLAAC).
- * Ensure the netif filters are configured accordingly!\n
+ * Ensure the netif filters are configured accordingly!<br>
  * The netif flags also need NETIF_FLAG_MLD6 flag set to enable MLD6 on a
- * netif ("netif->flags |= NETIF_FLAG_MLD6;").\n
+ * netif ("netif->flags |= NETIF_FLAG_MLD6;").<br>
  * To be called from TCPIP thread.
  */
 

src/core/netif.c

@@ -267,16 +267,16 @@ netif_add_noaddr(struct netif *netif, void *state, netif_init_fn init, netif_inp
  * @param state opaque data passed to the new netif
  * @param init callback function that initializes the interface
  * @param input callback function that is called to pass
- * ingress packets up in the protocol layer stack.\n
+ * ingress packets up in the protocol layer stack.<br>
  * It is recommended to use a function that passes the input directly
  * to the stack (netif_input(), NO_SYS=1 mode) or via sending a
- * message to TCPIP thread (tcpip_input(), NO_SYS=0 mode).\n
+ * message to TCPIP thread (tcpip_input(), NO_SYS=0 mode).<br>
  * These functions use netif flags NETIF_FLAG_ETHARP and NETIF_FLAG_ETHERNET
  * to decide whether to forward to ethernet_input() or ip_input().
  * In other words, the functions only work when the netif
- * driver is implemented correctly!\n
+ * driver is implemented correctly!<br>
  * Most members of struct netif should be be initialized by the
- * netif init function = netif driver (init parameter of this function).\n
+ * netif init function = netif driver (init parameter of this function).<br>
  * IPv6: Don't forget to call netif_create_ip6_linklocal_address() after
  * setting the MAC address in struct netif.hwaddr
  * (IPv6 requires a link-local address).

src/core/raw.c

@@ -2,14 +2,14 @@
  * @file
  * Implementation of raw protocol PCBs for low-level handling of
  * different types of protocols besides (or overriding) those
- * already available in lwIP.\n
+ * already available in lwIP.<br>
  * See also @ref raw_raw
  *
  * @defgroup raw_raw RAW
  * @ingroup callbackstyle_api
  * Implementation of raw protocol PCBs for low-level handling of
  * different types of protocols besides (or overriding) those
- * already available in lwIP.\n
+ * already available in lwIP.<br>
  * @see @ref api
  */
 

src/core/tcp.c

@@ -5,12 +5,12 @@
  *
  * @defgroup tcp_raw TCP
  * @ingroup callbackstyle_api
- * Transmission Control Protocol for IP\n
+ * Transmission Control Protocol for IP<br>
  * @see @ref api
  *
  * Common functions for the TCP implementation, such as functions
  * for manipulating the data structures and the TCP timer functions. TCP functions
- * related to input and output is found in tcp_in.c and tcp_out.c respectively.\n
+ * related to input and output is found in tcp_in.c and tcp_out.c respectively.<br>
  *
  * TCP connection setup
  * --------------------
@@ -2540,7 +2540,7 @@ tcp_pcbs_sane(void)
 /**
  * @defgroup tcp_raw_extargs ext arguments
  * @ingroup tcp_raw
- * Additional data storage per tcp pcb\n
+ * Additional data storage per tcp pcb<br>
  * @see @ref tcp_raw
  *
  * When LWIP_TCP_PCB_NUM_EXT_ARGS is > 0, every tcp pcb (including listen pcb)

src/core/udp.c

@@ -1,12 +1,12 @@
 /**
  * @file
- * User Datagram Protocol module\n
- * The code for the User Datagram Protocol UDP & UDPLite (RFC 3828).\n
+ * User Datagram Protocol module<br>
+ * The code for the User Datagram Protocol UDP & UDPLite (RFC 3828).<br>
  * See also @ref udp_raw
  *
  * @defgroup udp_raw UDP
  * @ingroup callbackstyle_api
- * User Datagram Protocol module\n
+ * User Datagram Protocol module<br>
  * @see @ref api
  */