docs: add a runnable syslog integration recipe

[chky1386]

Refs #42.

The cookbook shows how to format JSON but lacks an example of sending it to a log collection handler. Add a self-contained SysLogHandler recipe with a local UDP receiver and exact expected output, as suggested in #42.

Explain the syslog priority prefix, UTF-8 encoding, NUL terminator, and identifier so readers can configure their collector to parse the JSON payload. Include the standard HTTPHandler caveat from the original issue: attaching a formatter does not change its URL-encoded POST body into JSON. Add an Unreleased changelog entry; no runtime code or version change is needed.

Validation on Python 3.13.11 / macOS arm64:

• Executed the exact cookbook code block and checked its output, decoded fields, UTF-8, <14> prefix, absence of a NUL suffix, and resource cleanup.
• pytest: 218 passed.
• black --check --diff src tests, pylint src, mypy src tests, and validate-pyproject pyproject.toml: passed.
• Built the documentation and checked the rendered cookbook section.

Documentation tooling note: mkdocstrings-python 2.0.8 rejects the existing import configuration on unchanged main too. The preview was built with 1.19.0. Strict builds report the same seven existing API annotation warnings on both branches; a normal build succeeds. No dependency or configuration changes are included.

[nhairs]

Thanks for submitting this @chky1386, however I don't think this example is something we'd want to include.

Most of the example implementation is standard logging machinery, which per the docs:

This library assumes that you are famliar with the logging standard library package; if you are not you should start by reading the official Logging HOWTO.