Improve type mapping docs for Elasticsearch connector

[tlblessing]

Description

Improve type mapping documentation for Elasticsearch connector.

Is this change a fix, improvement, new feature, refactoring, or other?

Improvement to Elasticsearch connector documentation

How would you describe this change to a non-technical end user or system administrator?

Added data type mapping for write direction (Trino --> Elasticsearch); reformatted table for better wrapping; added boilerplate headings and verbiage for consistency.

Question for SMEs: I wasn't sure about the new write table to avoid 1:m mapping in the write direction. I assume that text might be preferred over keyword based on https://stackoverflow.com/questions/52845088/difference-between-keyword-and-text-in-elasticsearch. Please advise.

Documentation

( ) No documentation is needed.
(x) Sufficient documentation is included in this PR.
( ) Documentation PR is available with #prnumber.
( ) Documentation issue #issuenumber is filed, and can be handled later.

Release notes

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( ) Release notes entries required with the following suggested text:

[martint]

What does "modifies some types" mean in this context?

[jhlodin]

In the context of a read-only connector like this, just that the Elasticsearch data types are not necessarily the types used in Trino when reading, so some modification occurs in the engine/connector.

That ref link goes here, to this general type mapping explanation that just got merged earlier today - https://github.com/trinodb/trino/blob/master/docs/src/main/sphinx/language/types.rst#trino-type-support-and-mapping

[martint]

I think it's misleading. The types are not "modified", in the engine or elsewhere. The types from ES get mapped into Trino types, that's all.

[tlblessing]

@martint and @jhlodin can we change this to "maps some types"?

[jhlodin]

I think that works for me. Just make sure whatever wording gets merged here then gets applies to all other connectors.