Update ComDefaultInterfaceAttribute.xml (dotnet#5234)

Correct example snippet

Author: RussKie

xml/System.Runtime.InteropServices/ComDefaultInterfaceAttribute.xml

@@ -54,8 +54,12 @@
 ## Remarks  
  Compilers do not necessarily respect the order in which interfaces are implemented. For example, suppose you have the following code:  
   
-```  
-interface IBase {}interface IDerived : IBase {}class MyClass : IBase, IDerived {}  
+``` cs 
+interface IBase {}
+
+interface IDerived : IBase {}
+
+class MyClass : IBase, IDerived {}  
 ```  
   
  The compiler emits the implemented interfaces as `IDerived, IBase`. The ordering of interfaces is important  when using the <xref:System.Runtime.InteropServices.ClassInterfaceAttribute> class with `[ClassInterface(ClassInterfaceType.None)]` to expose an explicit interface as the default interface. Regardless of the specified `ClassInterfaceType`, use the <xref:System.Runtime.InteropServices.ComDefaultInterfaceAttribute> attribute to specify which interface should be recognized as the default.