Docs - Fixed input action C# issue

The `SetAction` and `SetPressed` are internal methods and can't be invoked directly outside of that assembly. However, the `Action` and `Pressed` property setters invoke them instead.

(cherry picked from commit 14e03b981f)

tutorials/inputs/inputevent.rst

@@ -234,8 +234,8 @@ The Input singleton has a method for this:
 
     var ev = new InputEventAction();
     // Set as ui_left, pressed.
-    ev.SetAction("ui_left");
-    ev.SetPressed(true);
+    ev.Action = "ui_left";
+    ev.Pressed = true;
     // Feedback.
     Input.ParseInputEvent(ev);