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

diff --git a/gtk/gtkcssprovider.c b/gtk/gtkcssprovider.c
index 6b9b1c7245a309490f513981a9f6c408e6460f25..a480dfb97a628fa7d3205c83b01c479f67f153a4 100644 (file)
--- 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>