Update 0.294 release notes about executable jars (#25982)

## Description
Update 0.294 release notes about executable jars, related to PR
prestodb/prestodb.github.io#303

## Motivation and Context
prestodb/prestodb.github.io#303

## Impact
0.294 release notes

## Test Plan
N/A

## Contributor checklist

- [ ] Please make sure your submission complies with our [contributing
guide](https://github.com/prestodb/presto/blob/master/CONTRIBUTING.md),
in particular [code
style](https://github.com/prestodb/presto/blob/master/CONTRIBUTING.md#code-style)
and [commit
standards](https://github.com/prestodb/presto/blob/master/CONTRIBUTING.md#commit-standards).
- [ ] PR description addresses the issue accurately and concisely. If
the change is non-trivial, a GitHub Issue is referenced.
- [ ] Documented new properties (with its default value), SQL syntax,
functions, or other functionality.
- [ ] If release notes are required, they follow the [release notes
guidelines](https://github.com/prestodb/presto/wiki/Release-Notes-Guidelines).
- [ ] Adequate tests were added if applicable.
- [ ] CI passed.

## Release Notes
Please follow [release notes
guidelines](https://github.com/prestodb/presto/wiki/Release-Notes-Guidelines)
and fill in the release notes below.

```
== NO RELEASE NOTE ==
```

## Summary by Sourcery

Documentation:
- Add details on building and running executable JARs in the 0.294
release notes

---------

Co-authored-by: sourcery-ai[bot] <58596630+sourcery-ai[bot]@users.noreply.github.com>
Co-authored-by: Steve Burnett <burnett@pobox.com>

Author: 3 people

presto-docs/src/main/sphinx/release/release-0.294.rst

@@ -12,6 +12,7 @@ Release 0.294
 * Add mixed case support for schema and table names. `#24551 <https://github.com/prestodb/presto/pull/24551>`_
 * Add case-sensitive support for column names. It can be enabled for JDBC based connector by setting ``case-sensitive-name-matching=true`` at the catalog level. `#24983 <https://github.com/prestodb/presto/pull/24983>`_
 * Update ``presto-plan-checker-router-plugin router`` plugin to use ``EXPLAIN (TYPE VALIDATE)`` in place of ``EXPLAIN (TYPE DISTRIBUTED)``, enabling faster routing of queries to either native or Java clusters. `#25545 <https://github.com/prestodb/presto/pull/25545>`_
+* From release 0.294, due to Maven Central publishing limitations, executable jar files including ``presto-cli``, ``presto-benchmark-driver``, and ``presto-test-server-launcher`` are no longer published in the Maven Central repository. These jars can now be found on the `Presto GitHub release page <https://github.com/prestodb/presto/releases/tag/0.294>`_.
 
 **Details**
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