pgsql: Standardize pg_authid oid_symbol values.

Standardize pg_authid oid_symbol values.

Commit c9c41c7a337d3e2deb0b2a193e9ecfb865d8f52b used two different
naming patterns.  Standardize on the majority pattern, which was the
only pattern in the last reviewed version of that commit.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/df5efaf4410f94cc1b69e8ade1d64dc92232ec1d

Modified Files
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src/backend/catalog/aclchk.c      | 8 ++++----
src/backend/commands/user.c       | 8 ++++----
src/backend/utils/adt/acl.c       | 6 +++---
src/include/catalog/pg_authid.dat | 6 +++---
4 files changed, 14 insertions(+), 14 deletions(-)