Set default return code to @ReturnCode

By convention, all of OnTopic's stored procedures use `@ReturnCode` as the return code. As such, this can be assumed as the default when calling `AddOutputParameter()`.

Author: JeremyCaney

OnTopic.Data.Sql/SqlCommandExtensions.cs

@@ -46,7 +46,7 @@ internal static int GetReturnCode(this SqlCommand command, string sqlParameter =
     /// <param name="sqlParameter">The SQL parameter.</param>
     /// <param name="paramDirection">The SQL parameter's directional setting (input-only, output-only, etc.).</param>
     /// <param name="sqlDbType">The SQL field data type.</param>
-    internal static void AddOutputParameter(this SqlCommand command, string sqlParameter) =>
+    internal static void AddOutputParameter(this SqlCommand command, string sqlParameter = "ReturnCode") =>
       AddParameter(command, sqlParameter, null, SqlDbType.Int, ParameterDirection.ReturnValue);
 
     /*==========================================================================================================================

OnTopic.Data.Sql/SqlTopicRepository.cs

@@ -339,7 +339,7 @@ public override Topic Load(string? topicKey = null, bool isRecursive = true) {
         | Establish query parameters
         \---------------------------------------------------------------------------------------------------------------------*/
         command.AddParameter("TopicKey", topicKey);
-        command.AddOutputParameter("ReturnCode");
+        command.AddOutputParameter();
 
         /*----------------------------------------------------------------------------------------------------------------------
         | Populate topics
@@ -763,7 +763,7 @@ public override int Save([NotNull]Topic topic, bool isRecursive = false, bool is
           command.AddParameter("DeleteRelationships", true);
         }
         command.AddParameter("ExtendedAttributes", extendedAttributes);
-        command.AddOutputParameter("ReturnCode");
+        command.AddOutputParameter();
 
         /*----------------------------------------------------------------------------------------------------------------------
         | Execute query