Add optional back

Jellyfin.Api/Controllers/TvShowsController.cs

@@ -65,7 +65,7 @@ namespace Jellyfin.Api.Controllers
         /// <param name="imageTypeLimit">Optional. The max number of images to return, per image type.</param>
         /// <param name="enableImageTypes">Optional. The image types to include in the output.</param>
         /// <param name="enableUserData">Optional. Include user data.</param>
-        /// <param name="nextUpDateCutoff">Starting date of shows to show in Next Up section.</param>
+        /// <param name="nextUpDateCutoff">Optional. Starting date of shows to show in Next Up section.</param>
         /// <param name="enableTotalRecordCount">Whether to enable the total records count. Defaults to true.</param>
         /// <param name="disableFirstEpisode">Whether to disable sending the first episode in a series as next up.</param>
         /// <returns>A <see cref="QueryResult{BaseItemDto}"/> with the next up episodes.</returns>