Fix some warnings in doxygen comments (#453)

Co-authored-by: Gaurav-Aggarwal-AWS <33462878+aggarg@users.noreply.github.com>
diff --git a/include/event_groups.h b/include/event_groups.h
index 48c8fdb..7a69805 100644
--- a/include/event_groups.h
+++ b/include/event_groups.h
@@ -65,8 +65,6 @@
  * be set and then tested atomically - as is the case where event groups are
  * used to create a synchronisation point between multiple tasks (a
  * 'rendezvous').
- *
- * \defgroup EventGroup
  */
 
 
diff --git a/include/task.h b/include/task.h
index f35a8d7..8921f10 100644
--- a/include/task.h
+++ b/include/task.h
@@ -1000,7 +1000,7 @@
  * filled with information about the task referenced by the handle passed using
  * the xTask parameter.
  *
- * @xGetFreeStackSpace The TaskStatus_t structure contains a member to report
+ * @param xGetFreeStackSpace The TaskStatus_t structure contains a member to report
  * the stack high water mark of the task being queried.  Calculating the stack
  * high water mark takes a relatively long time, and can make the system
  * temporarily unresponsive - so the xGetFreeStackSpace parameter is provided to