COMPMID-1008: Fix Doxygen issues

Change-Id: Ie73d8771f85d1f5b059f3a56f1bbd73c98e94a38
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/124723
Reviewed-by: Michalis Spyrou <michalis.spyrou@arm.com>
Tested-by: Jenkins <bsgcomp@arm.com>
diff --git a/arm_compute/runtime/Scheduler.h b/arm_compute/runtime/Scheduler.h
index 524622f..7e10461 100644
--- a/arm_compute/runtime/Scheduler.h
+++ b/arm_compute/runtime/Scheduler.h
@@ -33,12 +33,13 @@
 class Scheduler
 {
 public:
+    /** Scheduler type */
     enum class Type
     {
-        ST,    // Single thread.
-        CPP,   // C++11 threads.
-        OMP,   // OpenMP.
-        CUSTOM // Provided by the user.
+        ST,    /**< Single thread. */
+        CPP,   /**< C++11 threads. */
+        OMP,   /**< OpenMP. */
+        CUSTOM /**< Provided by the user. */
     };
     /** Sets the user defined scheduler and makes it the active scheduler.
      *
@@ -64,6 +65,8 @@
     static Type get_type();
     /** Returns true if the given scheduler type is supported. False otherwise.
      *
+     * @param[in] t the type of the scheduler to check.
+     *
      * @return true if the given scheduler type is supported. False otherwise.
      */
     static bool is_available(Type t);