[gtk+] scale: Document the new CSS nodes

[Matthias Clasen <matthiasc src gnome org>]

commit 60c7893c1445ac378a564e7342368f0dec73e61b
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Nov 6 19:38:50 2015 -0500

    scale: Document the new CSS nodes

 gtk/gtkscale.c |   14 ++++++++++++--
 1 files changed, 12 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkscale.c b/gtk/gtkscale.c
index 98c22c3..4b73c52 100644
--- a/gtk/gtkscale.c
+++ b/gtk/gtkscale.c
@@ -75,13 +75,15 @@
  * # CSS nodes
  *
  * |[<!-- language="plain" -->
- * scale
+ * scale[.fine-tune]
  * ├── marks.top
  * │   ├── mark
  * │   ├── mark
  * │   ╰── ...
  * ├── trough
- * │   ╰── slider
+ * │   ├──slider
+ * │   ├── [highlight]
+ * │   ╰── [fill]
  * ╰── marks.bottom
  *     ├── mark
  *     ├── mark
@@ -94,6 +96,14 @@
  * The main node gets the style class .fine-tune added when the scale is in
  * 'fine-tuning' mode.
  *
+ * If the scale has an origin (see gtk_scale_set_has_origin()), there is a
+ * subnode with name highlight below the trough node that is used for rendering
+ * the highlighted part of the trough.
+ *
+ * If the scale is showing a fill level (see gtk_range_set_show_fill_level()),
+ * there is a subnode with name fill below the trough node that is used for
+ * rendering the filled in part of the trough.
+ *
  * If marks are present, there is a marks subnode before or after the trough
  * node, below which each mark gets a node with name mark. The marks nodes get
  * either the .top or .bottom style class.