Обсуждение: pgsql: doc: Reword restriction on partition keys in unique indexes

doc: Reword restriction on partition keys in unique indexes

New wording from David G. Johnston, who noticed the unreadable original
also.  Include his suggested test case as well.

Fix a typo I noticed elsewhere while doing this.

Discussion: https://postgr.es/m/CAKFQuwY4Ld7ecxL_KAmaxwt0FUu5VcPPN2L4dh+3BeYbrdBa5g@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/63cbee6a786028790abc6ae9b9606366bae5e01d

Modified Files
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doc/src/sgml/ref/create_table.sgml        | 9 ++++-----
src/test/regress/expected/alter_table.out | 2 +-
src/test/regress/expected/indexing.out    | 8 ++++++++
src/test/regress/sql/alter_table.sql      | 2 +-
src/test/regress/sql/indexing.sql         | 7 +++++++
5 files changed, 21 insertions(+), 7 deletions(-)