[totem/mallard-documentation] Use proper markup for menuitem

[Andre Klapper <aklapper src gnome org>]

commit ab8049ef9146ff1564d2ec7e59ff5841845a981a
Author: Andre Klapper <a9016009 gmx de>
Date:   Wed Jan 9 23:56:44 2019 +0100

    Use proper markup for menuitem

 help/C/screenshot.page | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/help/C/screenshot.page b/help/C/screenshot.page
index f510f0fe..d8503c6b 100644
--- a/help/C/screenshot.page
+++ b/help/C/screenshot.page
@@ -28,7 +28,7 @@
   <steps>
     <item>
       <p>Press the menu button in the top-right corner of the window and select
-      <gui>Take Screenshot</gui>.</p>
+      <gui style="menuitem">Take Screenshot</gui>.</p>
     </item>
   </steps>