pgsql: Doc: fix some description of environment variables with frontend

Doc: fix some description of environment variables with frontend tools

This addresses a couple of issues in the documentation:
- Description of PG_COLOR was missing for some tools (pg_archivecleanup
and pg_test_fsync), while the other descriptions had grammar mistakes.
- pgbench supports more environment variables: PGUSER, PGHOST and
PGPORT.
- vacuumlo, oid2name and pgbench support coloring (HEAD only)

Author: Michael Paquier
Reviewed-by: Fabien Coelho, Daniel Gustafsson, Juan José Santamaría
Flecha
Discussion: https://postgr.es/m/20200304075418.GJ2593@paquier.xyz
Backpatch-through: 12

Branch
------
REL_12_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/654bd6985df897d3c9eb0be403e44d1871e4e352

Modified Files
--------------
doc/src/sgml/ref/clusterdb.sgml        |  4 ++--
doc/src/sgml/ref/createdb.sgml         |  4 ++--
doc/src/sgml/ref/createuser.sgml       |  4 ++--
doc/src/sgml/ref/dropdb.sgml           |  4 ++--
doc/src/sgml/ref/dropuser.sgml         |  4 ++--
doc/src/sgml/ref/initdb.sgml           |  4 ++--
doc/src/sgml/ref/pg_basebackup.sgml    |  4 ++--
doc/src/sgml/ref/pg_checksums.sgml     |  4 ++--
doc/src/sgml/ref/pg_controldata.sgml   |  4 ++--
doc/src/sgml/ref/pg_dump.sgml          |  4 ++--
doc/src/sgml/ref/pg_dumpall.sgml       |  4 ++--
doc/src/sgml/ref/pg_isready.sgml       |  4 ++--
doc/src/sgml/ref/pg_receivewal.sgml    |  4 ++--
doc/src/sgml/ref/pg_recvlogical.sgml   |  4 ++--
doc/src/sgml/ref/pg_resetwal.sgml      |  4 ++--
doc/src/sgml/ref/pg_restore.sgml       |  4 ++--
doc/src/sgml/ref/pg_rewind.sgml        |  4 ++--
doc/src/sgml/ref/pg_waldump.sgml       |  4 ++--
doc/src/sgml/ref/pgarchivecleanup.sgml | 12 ++++++++++++
doc/src/sgml/ref/pgbench.sgml          | 24 ++++++++++++++++++++++++
doc/src/sgml/ref/pgtestfsync.sgml      | 11 +++++++++++
doc/src/sgml/ref/psql-ref.sgml         |  4 ++--
doc/src/sgml/ref/reindexdb.sgml        |  4 ++--
doc/src/sgml/ref/vacuumdb.sgml         |  4 ++--
24 files changed, 89 insertions(+), 42 deletions(-)