[grilo] doc: Add unit to duration

[Juan A. Suarez Romero <jasuarez src gnome org>]

commit 8654445fae39768fcf776656e9c95133b21d9627
Author: Bastien Nocera <hadess hadess net>
Date:   Fri Jan 17 08:57:07 2014 +0100

    doc: Add unit to duration
    
    Looking at the various sources, this is currently in seconds
    
    https://bugzilla.gnome.org/show_bug.cgi?id=722398

 src/data/grl-media.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/data/grl-media.c b/src/data/grl-media.c
index e9cff52..1ad2f58 100644
--- a/src/data/grl-media.c
+++ b/src/data/grl-media.c
@@ -784,7 +784,7 @@ grl_media_set_site (GrlMedia *media, const gchar *site)
 /**
  * grl_media_set_duration:
  * @media: the media
- * @duration: the duration
+ * @duration: the duration in seconds
  *
  * Set the media's duration
  *
@@ -1371,7 +1371,7 @@ grl_media_get_site (GrlMedia *media)
  * grl_media_get_duration:
  * @media: the media object
  *
- * Returns: the media's duration
+ * Returns: the media's duration in seconds
  *
  * Since: 0.1.4
  */