Update Create an item section to improve coding practices, fix typo in comments.

Author: thisisbrianstewart

articles/cosmos-db/create-sql-api-dotnet.md

@@ -358,20 +358,17 @@ private async Task AddItemsToContainerAsync()
         IsRegistered = false
     };
 
-try
-{
-    // Read the item to see if it exists. ReadItemAsync will throw an exception if the item does not exist and return status code 404 (Not found).
-    ItemResponse<Family> andersenFamilyResponse = await this.container.ReadItemAsync<Family>(andersenFamily.Id, new PartitionKey(andersenFamily.LastName));
-    Console.WriteLine("Item in database with id: {0} already exists\n", andersenFamilyResponse.Resource.Id);
-}
-catch(CosmosException ex) when (ex.StatusCode == HttpStatusCode.NotFound)
-{
-    // Create an item in the container representing the Andersen family. Note we provide the value of the partition key for this item, which is "Andersen"
-    ItemResponse<Family> andersenFamilyResponse = await this.container.CreateItemAsync<Family>(andersenFamily, new PartitionKey(andersenFamily.LastName));
-
-    // Note that after creating the item, we can access the body of the item with the Resource property off the ItemResponse. We can also access the RequestCharge property to see the amount of RUs consumed on this request.
-    Console.WriteLine("Created item in database with id: {0} Operation consumed {1} RUs.\n", andersenFamilyResponse.Resource.Id, andersenFamilyResponse.RequestCharge);
-}
+    try
+    {
+        // Create an item in the container representing the Andersen family. Note we provide the value of the partition key for this item, which is "Andersen".
+        ItemResponse<Family> andersenFamilyResponse = await this.container.CreateItemAsync<Family>(andersenFamily, new PartitionKey(andersenFamily.LastName));
+        // Note that after creating the item, we can access the body of the item with the Resource property of the ItemResponse. We can also access the RequestCharge property to see the amount of RUs consumed on this request.
+        Console.WriteLine("Created item in database with id: {0} Operation consumed {1} RUs.\n", andersenFamilyResponse.Resource.Id, andersenFamilyResponse.RequestCharge);
+    }
+    catch (CosmosException ex) when (ex.StatusCode == HttpStatusCode.Conflict)
+    {
+        Console.WriteLine("Item in database with id: {0} already exists\n", andersenFamily.Id);                
+    }
 }
 
 ```