pgsql: psql: Improve tab completion for GRANT/REVOKE

psql: Improve tab completion for GRANT/REVOKE

This commit improves the handling of the following clauses:
- Addition of "CREATE" for ALTER DEFAULT PRIVILEGES .. GRANT/REVOKE.
- Addition of GRANT|ADMIN|INHERIT OPTION FOR for REVOKE, with some
completion for roles, INHERIT being added recently by e3ce2de.
- Addition of GRANT WITH ADMIN|INHERIT.

The list of privilege options common to GRANT and REVOKE is refactored
to avoid its duplication.

Author: Shi Yu
Reviewed-by: Kyotaro Horiguchi, Michael Paquier, Peter Smith
Discussion: https://postgr.es/m/OSZPR01MB6310FCE8609185A56344EED2FD559@OSZPR01MB6310.jpnprd01.prod.outlook.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/07f7237c2a3bcc2eebb554f812378188b07571bb

Modified Files
--------------
src/bin/psql/tab-complete.c | 53 +++++++++++++++++++++++----------------------
1 file changed, 27 insertions(+), 26 deletions(-)