pgsql: Show empty BRIN ranges in brin_page_items

Show empty BRIN ranges in brin_page_items

Commit 3581cbdcd6 added a flag to identify empty BRIN ranges. This adds
the new flag to brin_page_items() output.

This is kept as a separate commit as it should not be backpatched.

Reviewed-by: Justin Pryzby, Matthias van de Meent, Alvaro Herrera
Discussion: https://postgr.es/m/402430e4-7d9d-6cf1-09ef-464d80afff3b@enterprisedb.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/428c0cae929b7d2b26a830fbba55619c57ceba55

Modified Files
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contrib/pageinspect/brinfuncs.c                    | 10 ++++----
contrib/pageinspect/expected/brin.out              |  6 ++---
contrib/pageinspect/pageinspect--1.11--1.12.sql    | 17 +++++++++++++
doc/src/sgml/pageinspect.sgml                      | 16 ++++++-------
.../summarization-and-inprogress-insertion.out     | 28 +++++++++++-----------
5 files changed, 48 insertions(+), 29 deletions(-)