gh-87286: Add a number of LOG_* constants to syslog (#24432)

* bpo-43120: Add a number of LOG_* constants to syslog

This adds a number of syslog facilities to the syslogmodule.c.
These values are available on macOS.

* Switch contant documentation to the data directive

This fixes a CI warning and matches the pattern
used in the documentation for ``os``.

* Update Doc/library/syslog.rst


Co-authored-by: Hugo van Kemenade <hugovk@users.noreply.github.com>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>