pgsql: Correct some uses of e.g. and i.e. in message strings and docume

Correct some uses of e.g. and i.e. in message strings and documentation

E.g. means "for example" and i.e. means "that is". Fix a couple uses
that don't match the intended meaning.

Kyotaro Horiguchi

Reviewed by Junwang Zhao and Aleksander Alekseev, with one addition by me
Discussion: https://www.postgresql.org/message-id/flat/20220713.180943.589079824955875739.horikyota.ntt%40gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/82785effc01d4bf5f98ed9f12a75c48009ff4e7e

Modified Files
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doc/src/sgml/ecpg.sgml     | 2 +-
src/bin/pg_upgrade/check.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)