[gtk+] doc: Documented icon-shadow CSS property

[Matthias Clasen <matthiasc src gnome org>]

commit 29c7562ca7d168ab05ef1d186bdad5d0d58e0c33
Author: P. F. Chimento <philip chimento gmail com>
Date:   Wed Apr 17 10:33:43 2013 +0200

    doc: Documented icon-shadow CSS property
    
    The docs say that text-shadow applies a drop shadow to both text
    and icons, but icons need to use the icon-shadow property.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=698181

 gtk/gtkcssprovider.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)
---
diff --git a/gtk/gtkcssprovider.c b/gtk/gtkcssprovider.c
index 6b9b1c7..a480dfb 100644
--- a/gtk/gtkcssprovider.c
+++ b/gtk/gtkcssprovider.c
@@ -533,11 +533,15 @@
  * the GTK+ theming engine.
  * </para>
  * <para>
+ * To set a shadow on an icon, use the icon-shadow property instead,
+ * with the same syntax.
+ * </para>
+ * <para>
  * To set multiple shadows on an element, you can specify a comma-separated list
- * of shadow elements in the text-shadow property. Shadows are always rendered
- * front-back, i.e. the first shadow specified is on top of the others. Shadows
- * can thus overlay each other, but they can never overlay the text itself,
- * which is always rendered on top of the shadow layer.
+ * of shadow elements in the text-shadow or icon-shadow property. Shadows are
+ * always rendered front-back, i.e. the first shadow specified is on top of the
+ * others. Shadows can thus overlay each other, but they can never overlay the
+ * text or icon itself, which is always rendered on top of the shadow layer.
  * </para>
  * </refsect2>
  * <refsect2>