gst_webrtc_session_description_new: fix annotations
diff --git a/gst-libs/gst/webrtc/rtcsessiondescription.c b/gst-libs/gst/webrtc/rtcsessiondescription.c
index 3987ab6..af5cd1c 100644
--- a/gst-libs/gst/webrtc/rtcsessiondescription.c
+++ b/gst-libs/gst/webrtc/rtcsessiondescription.c
@@ -98,7 +98,7 @@
 /**
  * gst_webrtc_session_description_new:
  * @type: a #GstWebRTCSDPType
- * @sdp: a #GstSDPMessage
+ * @sdp: (transfer full): a #GstSDPMessage
  *
  * Returns: (transfer full): a new #GstWebRTCSessionDescription from @type
  *      and @sdp