Improve Javadoc for typeHint parameter

Link to an example type constant.

Change-Id: I214ab834fa02901a38e6048a94a5224b30c5d93f
Signed-off-by: Robin Stocker <robin@nibor.org>

org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectDatabase.java

 	 * @param objectId
 	 *            identity of the object to open.
 	 * @param typeHint
-	 *            hint about the type of object being requested;
-	 *            {@link ObjectReader#OBJ_ANY} if the object type is not known,
-	 *            or does not matter to the caller.
+	 *            hint about the type of object being requested, e.g.
+	 *            {@link Constants#OBJ_BLOB}; {@link ObjectReader#OBJ_ANY} if
+	 *            the object type is not known, or does not matter to the
+	 *            caller.
 	 * @return a {@link ObjectLoader} for accessing the object.
 	 * @throws MissingObjectException
 	 *             the object does not exist.

org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectReader.java

 	 * @param objectId
 	 *            identity of the object to test for existence of.
 	 * @param typeHint
-	 *            hint about the type of object being requested;
-	 *            {@link #OBJ_ANY} if the object type is not known, or does not
-	 *            matter to the caller.
+	 *            hint about the type of object being requested, e.g.
+	 *            {@link Constants#OBJ_BLOB}; {@link #OBJ_ANY} if the object
+	 *            type is not known, or does not matter to the caller.
 	 * @return true if the specified object is stored in this database.
 	 * @throws IncorrectObjectTypeException
 	 *             typeHint was not OBJ_ANY, and the object's actual type does
 	 * @param objectId
 	 *            identity of the object to open.
 	 * @param typeHint
-	 *            hint about the type of object being requested;
-	 *            {@link #OBJ_ANY} if the object type is not known, or does not
-	 *            matter to the caller.
+	 *            hint about the type of object being requested, e.g.
+	 *            {@link Constants#OBJ_BLOB}; {@link #OBJ_ANY} if the object
+	 *            type is not known, or does not matter to the caller.
 	 * @return a {@link ObjectLoader} for accessing the object.
 	 * @throws MissingObjectException
 	 *             the object does not exist.
 	 * @param objectId
 	 *            identity of the object to open.
 	 * @param typeHint
-	 *            hint about the type of object being requested;
-	 *            {@link #OBJ_ANY} if the object type is not known, or does not
-	 *            matter to the caller.
+	 *            hint about the type of object being requested, e.g.
+	 *            {@link Constants#OBJ_BLOB}; {@link #OBJ_ANY} if the object
+	 *            type is not known, or does not matter to the caller.
 	 * @return size of object in bytes.
 	 * @throws MissingObjectException
 	 *             the object does not exist.

org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java

 	 * @param objectId
 	 *            identity of the object to open.
 	 * @param typeHint
-	 *            hint about the type of object being requested;
-	 *            {@link ObjectReader#OBJ_ANY} if the object type is not known,
-	 *            or does not matter to the caller.
+	 *            hint about the type of object being requested, e.g.
+	 *            {@link Constants#OBJ_BLOB}; {@link ObjectReader#OBJ_ANY} if
+	 *            the object type is not known, or does not matter to the
+	 *            caller.
 	 * @return a {@link ObjectLoader} for accessing the object.
 	 * @throws MissingObjectException
 	 *             the object does not exist.