[gtk+] docs: Document gtk_recent_filter_filter() requirements

[Matthias Clasen <matthiasc src gnome org>]

commit baf4678087c1e4f4f8f7393c7850de968491980b
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sun Mar 23 08:12:09 2014 +1000

    docs: Document gtk_recent_filter_filter() requirements
    
    gtk_recent_filter_filter() needs the contains bitfield to be set, but
    this only mentions that the other fields are required.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=726900

 gtk/gtkrecentfilter.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkrecentfilter.c b/gtk/gtkrecentfilter.c
index 8b4f2f7..a346e80 100644
--- a/gtk/gtkrecentfilter.c
+++ b/gtk/gtkrecentfilter.c
@@ -695,7 +695,9 @@ gtk_recent_filter_add_custom (GtkRecentFilter      *filter,
  *
  * Tests whether a file should be displayed according to @filter.
  * The #GtkRecentFilterInfo @filter_info should include
- * the fields returned from gtk_recent_filter_get_needed().
+ * the fields returned from gtk_recent_filter_get_needed(), and
+ * must set the #GtkRecentFilterInfo.contains field of @filter_info
+ * to indicate which fields have been set.
  *
  * This function will not typically be used by applications; it
  * is intended principally for use in the implementation of