Fix typo in SceneLoader.cs (#495)

UOP1_Project/Assets/Scripts/SceneManagement/SceneLoader.cs

 			|| !_gameplayManagerSceneInstance.Scene.isLoaded)
 		{
 			_gameplayManagerLoadingOpHandle = _gameplayScene.sceneReference.LoadSceneAsync(LoadSceneMode.Additive, true);
-			_gameplayManagerLoadingOpHandle.Completed += OnGameplayMangersLoaded;
+			_gameplayManagerLoadingOpHandle.Completed += OnGameplayManagersLoaded;
 		}
 		else
 		{
 
-	private void OnGameplayMangersLoaded(AsyncOperationHandle<SceneInstance> obj)
+	private void OnGameplayManagersLoaded(AsyncOperationHandle<SceneInstance> obj)
 	{
 		_gameplayManagerSceneInstance = _gameplayManagerLoadingOpHandle.Result;