pgsql: doc: Fix syntax in ALTER FOREIGN DATA WRAPPER example

doc: Fix syntax in ALTER FOREIGN DATA WRAPPER example

The example for dropping an option was incorrectly quoting the
option key thus making it a value turning the command into an
unqualified ADD operation. The result of dropping became adding
a new key/value pair instead:

d=# alter foreign data wrapper f options (drop 'b');
ALTER FOREIGN DATA WRAPPER
d=# select fdwoptions from pg_foreign_data_wrapper where fdwname='f';
fdwoptions
------------
{drop=b}
(1 row)

This has been incorrect for a long time so backpatch to all
supported branches.

Author: Tim <tim(dot)needham2(at)gmail(dot)com>
Discussion: https://postgr.es/m/170292280173.1876505.5204623074024041738@wrigleys.postgresql.org

Branch
------
REL_12_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/3cf7dfa7f3f6432788bf1df026fe79b63ee98401

Modified Files
--------------
doc/src/sgml/ref/alter_foreign_data_wrapper.sgml | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)