Explicitly choose to run on all files

[EricE]

I just learned how to use git reset --hard (hardware guy, just learning Git) after fat fingering ssort without the file name... How about ssort . to explicitly say to process all files in the current file tree or maybe have a way to say all files in the current directory or all files in the current tree?

[bwhmather]

I was going to reluctantly close this as wontfix on the basis of precedent, but it seems that both isort and black both switched to this behaviour sometime in 2020. I think we can do something about this, but will require a little bit of imagination. Marking as a requirement for releasing 1.0.

[cgahr]

Closed by #84