Added %pr to CUSTOM_WPS to display remaining time in song.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@2072 a1c6a512-1295-4272-9138-f99709370657
diff --git a/docs/CUSTOM_WPS_FORMAT b/docs/CUSTOM_WPS_FORMAT
index 776135b..e4721bc 100644
--- a/docs/CUSTOM_WPS_FORMAT
+++ b/docs/CUSTOM_WPS_FORMAT
@@ -45,6 +45,7 @@
   %pp : Playlist Position
   %pe : Playlist Total Entries
   %pc : Current Time In Song
+  %pr : Remaining Time In Song
   %pt : Total Track Time
 Other Tags:
   %% : Displays a %