Write message for fluid.dataset~ without arguments

It wouldn’t be so bad if you could specify a relative path, or simply say write filename so it gets dumped in the same directory as the file, but fluid.dataset~ doesn’t seem to be happy with that either.

Yeah totally, hence the feature request-ness of this. Same goes for my request from a while back to be able to double-click fluid.dataset~ as well, which is also quite Max-y.