[tracker-miners] tracker-extract-gstreamer.c: Add comment

[Sam Thursfield <sthursfield src gnome org>]

commit 21ed37cddaf4bbb61bb4bfff46ba1dff016453f2
Author: Sam Thursfield <sam afuera me uk>
Date:   Sun Jul 14 11:29:37 2019 +0100

    tracker-extract-gstreamer.c: Add comment

 src/tracker-extract/tracker-extract-gstreamer.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/src/tracker-extract/tracker-extract-gstreamer.c b/src/tracker-extract/tracker-extract-gstreamer.c
index 84e7ce78f..96d70f228 100644
--- a/src/tracker-extract/tracker-extract-gstreamer.c
+++ b/src/tracker-extract/tracker-extract-gstreamer.c
@@ -363,6 +363,9 @@ get_embedded_cue_sheet_data (GstTagList *tag_list)
        return NULL;
 }
 
+/* Utility function to convert from GstToc, as returned by
+ * gst_discoverer_info_get_toc(), to TrackerToc.
+ */
 static TrackerToc *
 translate_discoverer_toc (GstToc *gst_toc)
 {