Markdown code block in TransactionEventArgs (#4511)

Previously used a number of single line code blocks with newline breaks between them

Author: Insomniak47

xml/System.Transactions/TransactionEventArgs.xml

@@ -38,24 +38,18 @@
 ## Examples  
  The following example demonstrates how this type is used.  
   
- `//Transaction completed event handler`  
-  
- `static void Current_TransactionCompleted(object sender, TransactionEventArgs e)`  
-  
- `{`  
-  
- `Console.WriteLine("A transaction has completed:");`  
-  
- `Console.WriteLine("ID:{0}",   e.Transaction.TransactionInformation.LocalIdentifier);`  
-  
- `Console.WriteLine("Distributed ID: {0}", e.Transaction.TransactionInformation.DistributedIdentifier);`  
-  
- `Console.WriteLine("Status:         {0}", e.Transaction.TransactionInformation.Status);`  
-  
- `Console.WriteLine("IsolationLevel: {0}", e.Transaction.IsolationLevel);`  
-  
- `}`  
+```cs
+ //Transaction completed event handler
+ static void Current_TransactionCompleted(object sender, TransactionEventArgs e)
+ {
   
+    Console.WriteLine("A transaction has completed:");
+    Console.WriteLine("ID:{0}",   e.Transaction.TransactionInformation.LocalIdentifier);
+    Console.WriteLine("Distributed ID: {0}", e.Transaction.TransactionInformation.DistributedIdentifier);
+    Console.WriteLine("Status:         {0}", e.Transaction.TransactionInformation.Status);
+    Console.WriteLine("IsolationLevel: {0}", e.Transaction.IsolationLevel);
+ }
+```
  ]]></format>
     </remarks>
   </Docs>