fix xmldoc warnings (#4779)

DevProject/Packages/manifest.json

   "dependencies": {
     "com.unity.2d.sprite": "1.0.0",
     "com.unity.2d.tilemap": "1.0.0",
-    "com.unity.ads": "3.4.7",
+    "com.unity.ads": "3.4.9",
     "com.unity.analytics": "3.3.5",
     "com.unity.coding": "0.1.0-preview.13",
     "com.unity.collab-proxy": "1.2.16",
     "com.unity.ml-agents.extensions": "file:../../com.unity.ml-agents.extensions",
     "com.unity.multiplayer-hlapi": "1.0.6",
-    "com.unity.package-manager-doctools": "1.1.1-preview.3",
-    "com.unity.package-validation-suite": "0.14.0-preview",
-    "com.unity.purchasing": "2.0.6",
-    "com.unity.test-framework": "1.1.14",
+    "com.unity.package-manager-doctools": "1.7.0-preview",
+    "com.unity.package-validation-suite": "0.19.0-preview",
+    "com.unity.purchasing": "2.1.0",
+    "com.unity.test-framework": "1.1.16",
     "com.unity.test-framework.performance": "2.2.0-preview",
     "com.unity.testtools.codecoverage": "0.2.2-preview",
     "com.unity.textmeshpro": "2.0.1",

com.unity.ml-agents/Runtime/Agent.deprecated.cs

         }
 
         /// <summary>
-        /// Deprecated, use <see cref="Heuristic(in ActionBuffers)"/> instead.
+        /// Deprecated, use <see cref="Heuristic(in Actuators.ActionBuffers)"/> instead.
         /// </summary>
         /// <param name="actionsOut"></param>
         [Obsolete("The float[] version of Heuristic has been deprecated, please use the ActionBuffers version instead.")]
         }
 
         /// <summary>
-        /// Deprecated, use <see cref="OnActionReceived(ActionBuffers)"/> instead.
+        /// Deprecated, use <see cref="OnActionReceived(Actuators.ActionBuffers)"/> instead.
         /// </summary>
         /// <param name="vectorAction"></param>
         [Obsolete("The float[] version of OnActionReceived has been deprecated, please use the ActionBuffers version instead.")]
         /// <returns>
         /// The last action that was decided by the Agent (or null if no decision has been made).
         /// </returns>
-        /// <seealso cref="OnActionReceived(ActionBuffers)"/>
+        /// <seealso cref="OnActionReceived(Actuators.ActionBuffers)"/>
         [Obsolete("GetAction has been deprecated, please use GetStoredActionBuffers instead.")]
         public float[] GetAction()
         {