[docs] add plat-infra-if and api-border-routing doxygen groups (#7898)

include/openthread/border_routing.h

@@ -44,7 +44,7 @@ extern "C" {
 #endif
 
 /**
- * @addtogroup api-border-router
+ * @addtogroup api-border-routing
  *
  * @brief
  *  This module includes definitions related to Border Routing Manager.

include/openthread/instance.h

@@ -53,7 +53,7 @@ extern "C" {
  * @note This number versions both OpenThread platform and user APIs.
  *
  */
-#define OPENTHREAD_API_VERSION (225)
+#define OPENTHREAD_API_VERSION (226)
 
 /**
  * @addtogroup api-instance

include/openthread/platform/infra_if.h

@@ -46,6 +46,16 @@
 extern "C" {
 #endif
 
+/**
+ * @addtogroup plat-infra-if
+ *
+ * @brief
+ *   This module includes the platform abstraction for the adjacent infrastructure network interface.
+ *
+ * @{
+ *
+ */
+
 /**
  * This method tells whether an infra interface has the given IPv6 address assigned.
  *
@@ -123,6 +133,11 @@ extern void otPlatInfraIfRecvIcmp6Nd(otInstance *        aInstance,
  */
 extern otError otPlatInfraIfStateChanged(otInstance *aInstance, uint32_t aInfraIfIndex, bool aIsRunning);
 
+/**
+ * @}
+ *
+ */
+
 #ifdef __cplusplus
 } // extern "C"
 #endif