code: public static PublishDelete createPublishDelete(Identifier i1, Identifier i2) {
  		return createPublishDelete(i1, i2, null);
  	}
docs: Create a new {@link PublishDelete} instance for a link between two
  {@link Identifier} instances in order to delete all metadata of the link.
  
  @param i1 the first {@link Identifier} of the link
  @param i2 the second {@link Identifier} of the link
  @return the new {@link PublishDelete} instance