pgsql: Rename amcancrosscompare

Rename amcancrosscompare

After more discussion about commit ce62f2f2a0a, rename the index AM
property amcancrosscompare to two separate properties
amconsistentequality and amconsistentordering.  Also improve the
documentation and update some comments that were previously missed.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/E1tngY6-0000UL-2n%40gemulon.postgresql.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/af4002b381d86df6479962953d82f03ecb4e2e06

Modified Files
--------------
contrib/bloom/blutils.c                          |  3 ++-
doc/src/sgml/indexam.sgml                        |  6 ++++--
src/backend/access/brin/brin.c                   |  3 ++-
src/backend/access/gin/ginutil.c                 |  3 ++-
src/backend/access/gist/gist.c                   |  3 ++-
src/backend/access/hash/hash.c                   |  3 ++-
src/backend/access/nbtree/nbtree.c               |  3 ++-
src/backend/access/spgist/spgutils.c             |  3 ++-
src/backend/optimizer/plan/analyzejoins.c        |  7 ++++---
src/backend/utils/cache/lsyscache.c              | 24 +++++++++++++-----------
src/include/access/amapi.h                       |  6 ++++--
src/test/modules/dummy_index_am/dummy_index_am.c |  3 ++-
12 files changed, 41 insertions(+), 26 deletions(-)