[gtk+/gtk-3-22] Frame: Explain the .flat style class

[Daniel Boles <dboles src gnome org>]

commit cc0e6eb37420189f14503179a3dd2e6852b26a7f
Author: Daniel Boles <dboles src gnome org>
Date:   Sun Feb 19 17:17:41 2017 +0000

    Frame: Explain the .flat style class

 gtk/gtkframe.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkframe.c b/gtk/gtkframe.c
index 56fb8c9..ed2ea68 100644
--- a/gtk/gtkframe.c
+++ b/gtk/gtkframe.c
@@ -81,7 +81,8 @@
  *
  * GtkFrame has a main CSS node with name frame and a subnode with
  * name border. The border node is used to render the visible border.
- * The style class .flat can appear with the main node.
+ * The main frame node can be given the style class .flat, which disables
+ * drawing of the border.
  */