pgsql: Improve psql's \d output for partitioned indexes.

Improve psql's \d output for partitioned indexes.

Include partitioning information much as we do for partitioned tables.
(However, \d+ doesn't show the partition bounds, because those are
not stored for indexes.)

In passing, fix a couple of queries to look less messy in -E output.

Also, add some tests for \d on tables with nondefault tablespaces.
(Somebody previously added a rather silly number of tests for \d
on partitioned indexes, yet completely neglected other cases.)

Justin Pryzby, reviewed by Fabien Coelho

Discussion: /messages/by-id/20190422154902.GH14223@telsasoft.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/24f62e93f314c107b4fa679869e5ba9adb2d545f

Modified Files
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src/bin/psql/describe.c | 114 +++++++++++++++---------------
src/test/regress/input/tablespace.source | 9 +++
src/test/regress/output/tablespace.source | 89 +++++++++++++++++++++++
3 files changed, 155 insertions(+), 57 deletions(-)