[.NET] Use collection expressions in docs

As of C# 12 we can now use collection expressions to reduce some boilerplate when initializing collections.

doc/classes/StringName.xml

@@ -546,7 +546,7 @@
 				print("---".join(fruits)) # Prints "Apple---Orange---Pear---Kiwi"
 				[/gdscript]
 				[csharp]
-				var fruits = new string[] {"Apple", "Orange", "Pear", "Kiwi"};
+				string[] fruits = ["Apple", "Orange", "Pear", "Kiwi"];
 
 				// In C#, this method is static.
 				GD.Print(string.Join(", ", fruits));  // Prints "Apple, Orange, Pear, Kiwi"