pgsql: doc: Improve {archive,restore}_command for compressed logs

doc: Improve {archive,restore}_command for compressed logs

The commands mentioned in the docs with gzip and gunzip did not prefix
the archives with ".gz" and used inconsistent paths for the archives,
which can be confusing.

Reported-by: Philipp Gramzow
Reviewed-by: Fujii Masao
Discussion: /messages/by-id/161397938841.15451.13129264141285167267@wrigleys.postgresql.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/329784e11849ff691f0157f3b27c50f652bce76a

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