[gnome-user-docs] Add notification bar shortcut introduced in bug 687986

[Andre Klapper <aklapper src gnome org>]

commit 55d713f8c73da5cb43f3bdf42cdcdfe1ca01952f
Author: Andre Klapper <a9016009 gmx de>
Date:   Tue Sep 4 16:38:17 2018 +0200

    Add notification bar shortcut introduced in bug 687986

 gnome-help/C/shell-keyboard-shortcuts.page | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/gnome-help/C/shell-keyboard-shortcuts.page b/gnome-help/C/shell-keyboard-shortcuts.page
index 21d7e0b8..88a4d5fc 100644
--- a/gnome-help/C/shell-keyboard-shortcuts.page
+++ b/gnome-help/C/shell-keyboard-shortcuts.page
@@ -125,9 +125,11 @@ information on navigating user interfaces with only the keyboard.</p>
     <td><p><link xref="shell-exit#lock-screen">Lock the screen.</link></p></td>
   </tr>
   <tr xml:id="super-m">
-    <td><p><keyseq><key>Super</key><key>M</key></keyseq></p></td>
+    <td><p><keyseq><key>Super</key><key>M</key></keyseq> or
+    <keyseq><key>Super</key><key>V</key></keyseq></p></td>
     <td><p>Open <link xref="shell-notifications#messagetray">the message
-    tray</link>. Press <keyseq><key>Super</key><key>M</key></keyseq> again or
+    tray</link>. Press <keyseq><key>Super</key><key>M</key></keyseq> or
+    <keyseq><key>Super</key><key>V</key></keyseq> again or
     <key>Esc</key> to close.</p></td>
   </tr>
 </table>