[gtk/ebassi/gidocgen: 301/478] popover: Use markdown for css tree

[Emmanuele Bassi <ebassi src gnome org>]

commit 1b011c9ddcccf5d695b5f688c59fcb979d6f78a7
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Feb 27 20:04:02 2021 -0500

    popover: Use markdown for css tree

 gtk/gtkpopover.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/gtk/gtkpopover.c b/gtk/gtkpopover.c
index a0c9752707..5c1953ddaf 100644
--- a/gtk/gtkpopover.c
+++ b/gtk/gtkpopover.c
@@ -46,7 +46,7 @@
  * is to use the [class@Gtk.PopoverMenu] subclass which supports being
  * populated from a `GMenuModel` with [ctor@Gtk.PopoverMenu.new_from_model].
  *
- * ```c
+ * ```xml
  * <section>
  *   <attribute name="display-hint">horizontal-buttons</attribute>
  *   <item>
@@ -69,12 +69,12 @@
  *
  * # CSS nodes
  *
- * |[<!-- language="plain" -->
+ * ```
  * popover[.menu]
  * ├── arrow
  * ╰── contents.background
  *     ╰── <child>
- * ]|
+ * ```
  *
  * The contents child node always gets the .background style class
  * and the popover itself gets the .menu style class if the popover