[totem/mallard-documentation] Cover keyboard shortcuts for zooming

[Andre Klapper <aklapper src gnome org>]

commit 59d816349950410108eec3f9aefadd770f3752cb
Author: Andre Klapper <a9016009 gmx de>
Date:   Fri Jan 11 20:04:16 2019 +0100

    Cover keyboard shortcuts for zooming

 help/C/view-zoom.page | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/help/C/view-zoom.page b/help/C/view-zoom.page
index df0ea40f..8b805c6b 100644
--- a/help/C/view-zoom.page
+++ b/help/C/view-zoom.page
@@ -35,7 +35,8 @@
     <item>
       <title><code>Zoom in</code></title>
       <p>Press the menu button in the top-right corner of the window and select
-      <gui style="menuitem">Zoom In</gui>.</p>
+      <gui style="menuitem">Zoom In</gui> or press <key>R</key>. To zoom out,
+      disable <gui style="menuitem">Zoom In</gui> again or press <key>T</key>.</p>
     </item>
     <item>
       <title><code>Setting aspect ratio</code></title>