[libgdata] calendar: Expand the documentation for GDataCalendarCalendar:color slightly

[Philip Withnall <pwithnall src gnome org>]

commit 11acc9979f50d577d501ddc7328739801964a83a
Author: Philip Withnall <philip tecnocode co uk>
Date:   Sat Jul 2 19:26:24 2011 +0100

    calendar: Expand the documentation for GDataCalendarCalendar:color slightly
    
    It turns out that only a limited palette of colours is allowed.

 gdata/services/calendar/gdata-calendar-calendar.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/gdata/services/calendar/gdata-calendar-calendar.c b/gdata/services/calendar/gdata-calendar-calendar.c
index e548649..3b4d79a 100644
--- a/gdata/services/calendar/gdata-calendar-calendar.c
+++ b/gdata/services/calendar/gdata-calendar-calendar.c
@@ -181,7 +181,8 @@ gdata_calendar_calendar_class_init (GDataCalendarCalendarClass *klass)
 	/**
 	 * GDataCalendarCalendar:color:
 	 *
-	 * The color used to highlight the calendar in the user's browser.
+	 * The color used to highlight the calendar in the user's browser. This must be one of a limited set of colors listed in the
+	 * <ulink type="http" url="http://code.google.com/apis/calendar/data/2.0/reference.html#gCalcolor";>online documentation</ulink>.
 	 **/
 	g_object_class_install_property (gobject_class, PROP_COLOR,
 	                                 g_param_spec_boxed ("color",