Doc: shallow clone deepens _to_ new depth Clarify that 'depth=' specifies the new depth from the remote's branch tip. It does not add the depth to the existing shallow clone. (details from pack-protocol.txt). Clarify that tags are not fetched. (details from shallow.txt) Signed-off-by: Philip Oakley <philipoakley@iee.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>