pgsql: Doc: correct thinko in pg_buffercache documentation.

Doc: correct thinko in pg_buffercache documentation.

Access to this module is granted to the pg_monitor role, not
pg_read_all_stats.  (Given the view's performance impact,
it seems wise to be restrictive, so I think this was the
correct decision --- and anyway it was clearly intentional.)

Per bug #16279 from Philip Semanchuk.

Discussion: https://postgr.es/m/16279-fcaac33c68aab0ab@postgresql.org

Branch
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REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/880643b9cd1b87c1afb376a9f9a6f5a1df7aa644

Modified Files
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doc/src/sgml/pgbuffercache.sgml | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)