pgsql: Doc: improve documentation about ORDER BY in matviews.

Doc: improve documentation about ORDER BY in matviews.

Remove the confusing use of ORDER BY in an example materialized
view.  It adds nothing to the example, but might encourage
people to follow bad practice.  Clarify REFRESH MATERIALIZED
VIEW's note about whether view ordering is retained (it isn't).

Maciek Sakrejda

Discussion: https://postgr.es/m/CAOtHd0D-OvrUU0C=4hX28p4BaSE1XL78BAQ0VcDaLLt8tdUzsg@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/4f33af23e7e3ac30b3cb9480981c3accf401ef01

Modified Files
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doc/src/sgml/ref/refresh_materialized_view.sgml | 10 ++++------
doc/src/sgml/rules.sgml                         |  3 ---
2 files changed, 4 insertions(+), 9 deletions(-)