SubmoduleWalk#forPath: Clarify that caller must close returned instance

Change-Id: I25e7913a78c23c030a8c568975ee1044a9973517
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

org.eclipse.jgit/src/org/eclipse/jgit/submodule/SubmoduleWalk.java

@@ -144,7 +144,8 @@ public class SubmoduleWalk implements AutoCloseable {
 	 *            path and .gitmodules at the root.
 	 * @param path
 	 *            a {@link java.lang.String} object.
-	 * @return generator at given path, null if no submodule at given path
+	 * @return generator at given path. The caller is responsible for calling
+	 *         {@link #close()}. Null if no submodule at given path.
 	 * @throws java.io.IOException
 	 */
 	public static SubmoduleWalk forPath(Repository repository,
@@ -177,7 +178,8 @@ public class SubmoduleWalk implements AutoCloseable {
 	 *            path and .gitmodules at the root.
 	 * @param path
 	 *            a {@link java.lang.String} object.
-	 * @return generator at given path, null if no submodule at given path
+	 * @return generator at given path. The caller is responsible for calling
+	 *         {@link #close()}. Null if no submodule at given path.
 	 * @throws java.io.IOException
 	 */
 	public static SubmoduleWalk forPath(Repository repository,