frame: Use markdown for css tree

diff --git a/gtk/gtkframe.c b/gtk/gtkframe.c
index 392fed5abf9061600ada386f7751bf4e33634016..4d99dc4312d4a49299ef4d3b515addfe37b03fd8 100644 (file)
--- a/gtk/gtkframe.c
+++ b/gtk/gtkframe.c
@@ -69,11 +69,11 @@
  *
  * # CSS nodes
  *
- * |[<!-- language="plain" -->
+ * ```
  * frame
  * ├── <label widget>
  * ╰── <child>
- * ]|
+ * ```
  *
  * `GtkFrame` has a main CSS node with name “frame”, which is used to draw the
  * visible border. You can set the appearance of the border using CSS properties