tests: events: fix doxygen groups

Fix grouping and general doxygen fixups.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

tests/kernel/events/event_api/src/main.c

@@ -17,7 +17,7 @@
  *   -# k_event_wait_all
  *   -# k_event_test
  *
- * @defgroup kernel_event_tests events
+ * @defgroup kernel_event_tests Events
  * @ingroup all_tests
  * @{
  * @}

tests/kernel/events/event_api/src/test_event_apis.c

@@ -46,6 +46,10 @@ static void entry_extra2(void *p1, void *p2, void *p3)
 
 	k_event_post(&test_event, events);
 }
+/**
+* @ingroup kernel_event_tests
+* @{
+*/
 
 /**
  * Test the k_event_init() API.
@@ -53,7 +57,6 @@ static void entry_extra2(void *p1, void *p2, void *p3)
  * This is a white-box test to verify that the k_event_init() API initializes
  * the fields of a k_event structure as expected.
  */
-
 ZTEST(events_api, test_k_event_init)
 {
 	static struct k_event  event;
@@ -431,3 +434,6 @@ ZTEST(events_api, test_event_receive)
 
 	test_wake_multiple_threads();
 }
+/**
+ * @}
+ */

tests/kernel/events/sys_event/src/main.c

@@ -34,10 +34,8 @@ static K_SEM_DEFINE(sync_sem, 0, 1);
 volatile static uint32_t test_events;
 
 /**
- * @defgroup kernel_sys_events_tests Semaphore
- * @ingroup all_tests
+ * @ingroup kernel_event_tests
  * @{
- * @}
  */
 
 static void entry_extra1(void *p1, void *p2, void *p3)
@@ -404,5 +402,8 @@ void *sys_events_setup(void)
 	return NULL;
 }
 
+/**
+ * @}
+ */
 ZTEST_SUITE(sys_events, NULL, sys_events_setup,
 		ztest_simple_1cpu_before, ztest_simple_1cpu_after, NULL);