[evince/mallard-docs] docs: formats.page, added note about backend for formats.

[Tiffany Antopolski <antopolski src gnome org>]

commit 255a258d0fa5ba41fd859083430ba1578948041a
Author: Tiffany Antopolski <antopolski src gnome org>
Date:   Mon Nov 15 21:57:21 2010 -0500

    docs: formats.page, added note about backend for formats.

 help/C/formats.page |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)
---
diff --git a/help/C/formats.page b/help/C/formats.page
index 5181d54..290576c 100644
--- a/help/C/formats.page
+++ b/help/C/formats.page
@@ -35,8 +35,16 @@
  <item><p>Scalable Vector Graphics (.svg)</p></item>
  <item><p>Tagged Image File Format (.tiff, .tif)</p></item>
  <item><p>Other Image Files (.gif, .jpeg, .png)</p></item>
+</list>
+<note>
+<p>
+In some Linux distributions, not all formats are supported by default, so you might not be able to view all the formats listed above.  
+</p>
+<p>
+Support for a format is called a <em>backend</em>.  If <app>Evince</app> gives you the error "Unable to Open Document", you may wish to check whether the backend package for the format is installed.
+</p>
+</note>
 
 
-</list>
 
 </page>