Consider adding thread's "native_id" to the record attributes

[Delgan]

See https://github.com/Delgan/loguru/issues/936.

I feel using the OS thread id would more useful than the Python thread identifier. Especially because this can be mapped with external tools (such as Sentry).

I suggest to rename current "{thread.id}" to "{thread.ident}", then assign native_id() output to "{thread.id}".