[COMMITTERS] pgsql: Improve error reporting for tuple-routing failures.

Improve error reporting for tuple-routing failures.

Currently, the whole row is shown without column names.  Instead,
adopt a style similar to _bt_check_unique() in ExecFindPartition()
and show the failing key: (key1, ...) = (val1, ...).

Amit Langote, per a complaint from Simon Riggs.  Reviewed by me;
I also adjusted the grammar in one of the comments.

Discussion: http://postgr.es/m/9f9dc7ae-14f0-4a25-5485-964d9bfc19bd@lab.ntt.co.jp

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/5a73e17317e91912b2755f7960d5bf31d374cf31

Modified Files
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src/backend/access/index/genam.c     |   4 ++
src/backend/catalog/partition.c      |  30 ++++----
src/backend/executor/execMain.c      | 132 ++++++++++++++++++++++++++++++-----
src/backend/utils/adt/ruleutils.c    |  37 +++++++---
src/include/catalog/partition.h      |   8 ++-
src/include/utils/ruleutils.h        |   2 +
src/test/regress/expected/insert.out |  38 ++++++++--
src/test/regress/sql/insert.sql      |  30 ++++++++
8 files changed, 231 insertions(+), 50 deletions(-)