LUCENE-2328: add jdoc details for deprecation of Directory.sync(String)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@926948 13f79535-47bb-0310-9956-ffa450edef68

lucene/src/java/org/apache/lucene/store/Directory.java

@@ -85,6 +85,9 @@ public abstract class Directory implements Closeable {
    * stable storage.  Lucene uses this to properly commit
    * changes to the index, to prevent a machine/OS crash
    * from corrupting the index.
+   * @deprecated use {@link #sync(Collection)} instead.
+   * For easy migration you can change your code to call
+   * sync(Collections.singleton(name))
    */
   @Deprecated
   public void sync(String name) throws IOException { // TODO 4.0 kill me