fix jsdoc tag, makes Closure Compiler happy. no functional change

git-svn-id: http://svn.openlayers.org/trunk/openlayers@12278 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Tile/BackBufferable.js

@@ -4,12 +4,12 @@
  * full text of the license. */
 
 
-/*
+/**
  * @requires OpenLayers/Tile.js
  * @requires OpenLayers/Util.js
  */
 
-/*
+/**
  * Class: OpenLayers.Tile.BackBufferable
  * Base class for tiles that can have backbuffers during transitions. Do not
  * create instances of this class.
@@ -198,4 +198,4 @@ OpenLayers.Tile.BackBufferable = OpenLayers.Class(OpenLayers.Tile, {
         OpenLayers.Tile.prototype.destroy.apply(this, arguments);
     }
         
-});
+});