Document polymorphic table functions not preserving row ordering

[jhlodin]

Description

See #14401 (review) for context

Non-technical explanation

Polymorphic table functions don't preserve row ordering, so this PR documents that limitation

Release notes

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# Section
* Fix some things. ({issue}`issuenumber`)

[martint]

This is not a limitation. It's just how the SQL language works. The ORDER BY clause is a clause for the polymorphic table function, not for the query. It's for sorting inputs to the table function, but has no bearing or relationship to how the outputs of the table function come out. In a way, it's similar to ORDER BY appearing in window functions or subqueries.

[findepi]

This is not a limitation. It's just how the SQL language works.

i know and you know i know.

Still, some users were seen doing

SELECT * FORM TABLE ( catalog.system.query(' ... ORDER BY ...'))

and it's good to explain them that it's kind of pointless.
especially that, for some connectors, under some circumstances, this may actually return results sorted, so a user may concluded based on observations, that this works as they want

[martint]

Oh, that's different. I thought it was referring to the ORDER BY clause in the polymorphic table function invocation:

SELECT * FROM TABLE(table_function(
    input => TABLE(...) ORDER BY ...
))

In that case, yes, I agree with @findepi. This should go in the documentation for the specific table functions.

[jhlodin]

Reworked to include this note as a fragment in the query table function sections of applicable connectors, PTAL.

[jhlodin]

This PR has been rebased to master and builds fine locally, so I'm not sure why checks are failing.

[jhlodin]

@findepi Have I addressed all feedback/can we merge this?