Document that watch is not supported on windows

[CaselIT]

Issues

Watch requires the signal SIGHUP that is only available on unix type system.

What OS are you using?

windows

What version of Dramatiq are you using?

1.9.0

What did you do?

started dramatiq with the --watch option and modified the files causing a reload

What did you expect would happen?

The code would reload. Or a meaningful error would be raised.

What happened?

The excection AttributeError: module 'signal' has no attribute 'SIGHUP' is raised.

While it would be nice to have support for reload on windows, I think its would be ok to just document that watch is not supported in dramatiq --help and maybe ignore the flag on windows or raise a more meaningful exception than the attribute error

[Bogdanp]

This makes sense to me. Would you like to make these changes?

[CaselIT]

Ok, I'll have a look at it. I think that documenting that watch on windows is not supported and ignore the flag would be preferred option for now? Alternatively I'm not sure if we could change SIGHUP for another signal on windows to make watch work?

[Bogdanp]

I think that documenting that watch on windows is not supported and ignore the flag would be preferred option for now?

Yep. That sounds like the right approach. Maybe raise a specific error when --watch is set on Windows instead of ignoring it.