pgsql: psql: Add tab completion for subscription wal_receiver_timeout

psql: Add tab completion for subscription wal_receiver_timeout

Commit fb80f388f added wal_receiver_timeout as a CREATE/ALTER
SUBSCRIPTION option, but psql tab completion did not include it in the
subscription option lists.

Add wal_receiver_timeout to completion for CREATE SUBSCRIPTION ... WITH
and ALTER SUBSCRIPTION ... SET.

Author: Chao Li <lic(at)highgo(dot)com>
Reviewed-by: Bharath Rupireddy <bharath(dot)rupireddyforpostgres(at)gmail(dot)com>
Reviewed-by: Xuneng Zhou <xunengzhou(at)gmail(dot)com>
Reviewed-by: Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
Discussion: https://postgr.es/m/BBC5628A-63C0-4436-B8F3-90AF59BBEB73@gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/56b2792cf84fc78f9109b0ae122174e70379ad07

Modified Files
--------------
src/bin/psql/tab-complete.in.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)