C#: Fix Shortcut example

- Follow our code-style and conventions.
- Match the GDScript example more closely.
- Replace `set_events()` method with `events` property.

doc/classes/Shortcut.xml

@@ -16,8 +16,8 @@
 			var key_event = InputEventKey.new()
 			key_event.keycode = KEY_S
 			key_event.ctrl_pressed = true
-			key_event.command_or_control_autoremap = true # Swaps ctrl for Command on Mac.
-			save_shortcut.set_events([key_event])
+			key_event.command_or_control_autoremap = true # Swaps Ctrl for Command on Mac.
+			save_shortcut.events = [key_event]
 
 		func _input(event):
 			if save_shortcut.matches_event(event) and event.is_pressed() and not event.is_echo():
@@ -25,39 +25,35 @@
 				get_viewport().set_input_as_handled()
 		[/gdscript]
 		[csharp]
-		public partial class YourScriptName : Godot.Node
+		using Godot;
+
+		public partial class MyNode : Node
+		{
+			private readonly Shortcut _saveShortcut = new Shortcut();
+
+			public override void _Ready()
 			{
-				private Godot.Shortcut saveShortcut;
-
-				public override void _Ready()
+				InputEventKey keyEvent = new InputEventKey
 				{
-					// Enable input processing explicitly (optional for Node, but included for clarity)
-					SetProcessInput(true);
+					Keycode = Key.S,
+					CtrlPressed = true,
+					CommandOrControlAutoremap = true, // Swaps Ctrl for Command on Mac.
+				};
 
-					saveShortcut = new Godot.Shortcut();
+				_saveShortcut.Events = [keyEvent];
+			}
 
-					Godot.InputEventKey keyEvent = new Godot.InputEventKey
-					{
-						Keycode = Godot.Key.S,
-						CtrlPressed = true,
-						CommandOrControlAutoremap = true
-					};
-
-					Godot.Collections.Array<Godot.InputEvent> events = new Godot.Collections.Array<Godot.InputEvent> { keyEvent };
-					saveShortcut.SetEvents(events);
-				}
-
-				public override void _Input(Godot.InputEvent @event)
+			public override void _Input(InputEvent @event)
+			{
+				if (@event is InputEventKey keyEvent &&
+					_saveShortcut.MatchesEvent(@event) &&
+					keyEvent.Pressed && !keyEvent.Echo)
 				{
-					if (@event is Godot.InputEventKey keyEvent &&
-						saveShortcut.MatchesEvent(@event) &&
-						keyEvent.Pressed && !keyEvent.Echo)
-					{
-						Godot.GD.Print("Save shortcut pressed!");
-						GetViewport().SetInputAsHandled();
-					}
+					GD.Print("Save shortcut pressed!");
+					GetViewport().SetInputAsHandled();
 				}
 			}
+		}
 		[/csharp]
 		[/codeblocks]
 	</description>