[gtk/ebassi/gidocgen] colorbutton: Use markdown for css tree

[Matthias Clasen <matthiasc src gnome org>]

commit 340b36d143a004c83e30e690be37ebbd7f652f6b
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Feb 27 19:45:07 2021 -0500

    colorbutton: Use markdown for css tree

 gtk/gtkcolorbutton.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkcolorbutton.c b/gtk/gtkcolorbutton.c
index 8d2c7f06dc..90d3225351 100644
--- a/gtk/gtkcolorbutton.c
+++ b/gtk/gtkcolorbutton.c
@@ -58,11 +58,11 @@
  *
  * # CSS nodes
  *
- * |[<!-- language="plain" -->
+ * ```
  * colorbutton
  * ╰── button.color
  *     ╰── [content]
- *]|
+ * ```
  *
  * `GtkColorButton` has a single CSS node with name colorbutton which
  * contains a button node. To differentiate it from a plain `GtkButton`,