Fix date typos and terminology in default interface methods tutorial (#47375)

* Initial plan

* Fix date typos and terminology in default interface methods tutorial

Co-authored-by: BillWagner <[email protected]>

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: BillWagner <[email protected]>

Author: Copilot

docs/csharp/advanced-topics/interface-implementation/default-interface-methods-versions.md

@@ -58,7 +58,7 @@ Notice the following portion of the test:
 
 :::code language="csharp" source="./snippets/default-interface-members-versions/finished/customer-relationship/Program.cs" id="SnippetHighlightCast":::
 
-That cast from `SampleCustomer` to `ICustomer` is necessary. The `SampleCustomer` class doesn't need to provide an implementation for `ComputeLoyaltyDiscount`; that's provided by the `ICustomer` interface. However, the `SampleCustomer` class doesn't inherit members from its interfaces. That rule hasn't changed. In order to call any method declared and implemented in the interface, the variable must be the type of the interface, `ICustomer` in this example.
+That implicit conversion from `SampleCustomer` to `ICustomer` is necessary. The `SampleCustomer` class doesn't need to provide an implementation for `ComputeLoyaltyDiscount`; that's provided by the `ICustomer` interface. However, the `SampleCustomer` class doesn't inherit members from its interfaces. That rule hasn't changed. In order to call any method declared and implemented in the interface, the variable must be the type of the interface, `ICustomer` in this example.
 
 ## Provide parameterization
 

docs/csharp/advanced-topics/interface-implementation/snippets/default-interface-members-versions/finished/customer-relationship/Program.cs

@@ -5,14 +5,14 @@
     Reminders =
     {
         { new DateTime(2010, 08, 12), "childs's birthday" },
-        { new DateTime(1012, 11, 15), "anniversary" }
+        { new DateTime(2012, 11, 15), "anniversary" }
     }
 };
 
 SampleOrder o = new SampleOrder(new DateTime(2012, 6, 1), 5m);
 c.AddOrder(o);
 
-o = new SampleOrder(new DateTime(2103, 7, 4), 25m);
+o = new SampleOrder(new DateTime(2013, 7, 4), 25m);
 c.AddOrder(o);
 
 // <SnippetHighlightCast>

docs/csharp/advanced-topics/interface-implementation/snippets/default-interface-members-versions/starter/customer-relationship/Program.cs

@@ -5,14 +5,14 @@
     Reminders =
     {
         { new DateTime(2010, 08, 12), "childs's birthday" },
-        { new DateTime(1012, 11, 15), "anniversary" }
+        { new DateTime(2012, 11, 15), "anniversary" }
     }
 };
 
 SampleOrder o = new SampleOrder(new DateTime(2012, 6, 1), 5m);
 c.AddOrder(o);
 
-o = new SampleOrder(new DateTime(2103, 7, 4), 25m);
+o = new SampleOrder(new DateTime(2013, 7, 4), 25m);
 c.AddOrder(o);
 
 Console.WriteLine($"Data about {c.Name}");