[gnome-boxes] help: Update the label for create new box button

[Felipe Borges <felipeborges src gnome org>]

commit 29bf4346f503af7bcb0fa241e70f76036e0c2dc8
Author: Dominika Vagnerova <domi vagn gmail com>
Date:   Thu Sep 5 14:18:33 2019 +0200

    help: Update the label for create new box button

 help/C/create.page | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/help/C/create.page b/help/C/create.page
index 65a62955..2c2d33ac 100644
--- a/help/C/create.page
+++ b/help/C/create.page
@@ -15,7 +15,7 @@
 
     <include href="legal.xml" xmlns="http://www.w3.org/2001/XInclude"/>
 
-    <desc>Click <gui style="button">New</gui> to begin creating a box.</desc>
+    <desc>Click <gui style="button">+</gui> to begin creating a box.</desc>
   </info>
 
   <title>Create a box</title>