Add +(pg_lsn,numeric) and -(pg_lsn,numeric) operators.
By using these operators, the number of bytes can be added into and
subtracted from LSN.
Bump catalog version.
Author: Fujii Masao
Reviewed-by: Kyotaro Horiguchi, Michael Paquier, Asif Rehman
Discussion: https://postgr.es/m/
ed9f7f74-e996-67f8-554a-
52ebd3779b3b@oss.nttdata.com