simplify using

Author: christiannagel

1_CS/Collections/ImmutableCollectionSample/GlobalUsings.cs

@@ -1,4 +1,6 @@
-SimpleArrayDemo();
+using System.Collections.Immutable;
+
+SimpleArrayDemo();
 ImmutableList<Account> accounts = CreateImmutableList();
 UsingABuilder(accounts);
 LinqDemo();