Fix TextInput.OnInput not firing on Wayland

Platforms like Wayland require calling TextInputEXT.StartTextInput()
before any events are fired. With the addition, input on the debug
console and CelestNet chat will work under Wayland, whereas before both
accepted no input after being opened.

Celeste.Mod.mm/Mod/Everest/TextInput.cs

@@ -31,6 +31,10 @@ internal static void Initialize(Game game) {
                 // public static event Action<char> TextInput;
                 e_TextInput.AddEventHandler(null, new Action<char>(ReceiveTextInput).CastDelegate(e_TextInput.EventHandlerType));
 
+                // Some platforms like Linux/Wayland may require calling TextInputEXT.StartTextInput to receive events for TextInputEXT.TextInput
+                MethodInfo e_StartTextInput = t_TextInputExt?.GetMethod("StartTextInput", new Type[] { } );
+                e_StartTextInput?.Invoke(t_TextInputExt, null);
+
                 // SDL2 offers SDL_GetClipboardText and SDL_SetClipboardText
                 Type t_SDL2 = typeof(Keyboard).Assembly.GetType("SDL2.SDL");
                 _GetClipboardText = t_SDL2.GetMethod("SDL_GetClipboardText").CreateDelegate(typeof(Func<string>)) as Func<string>;