As the info returned is a new object, the annotation should be transfer-full,
similarly to the get_current_{audio,video}_track() implementations.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1775>
*
* A Function to get current subtitle #GstPlayerSubtitleInfo instance.
*
- * Returns: (transfer none): current subtitle track.
+ * Returns: (transfer full): current subtitle track.
*
* The caller should free it with g_object_unref()
*/