pgsql: improve hash creation warning message

improve hash creation warning message

This improves the wording of commit 84aa8ba128a08e6fdebb2497c7a79ebf18093e12.

Report by Kevin Grittner

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/849462a9fafbb30856e47f7862543b1aefa95796

Modified Files
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src/backend/commands/indexcmds.c               |    2 +-
src/test/regress/expected/create_index.out     |    8 ++++----
src/test/regress/expected/enum.out             |    2 +-
src/test/regress/expected/macaddr.out          |    2 +-
src/test/regress/expected/replica_identity.out |    2 +-
src/test/regress/expected/uuid.out             |    2 +-
6 files changed, 9 insertions(+), 9 deletions(-)