Feature Request: sync doesn't seem to allow syncing from remote to local

[znation]

Attempting to sync from remote to local gives the error:

(venv) ➜ xet sync xet://XetHub/Falcon-RefinedWeb/main Falcon-RefinedWeb-download
Checking sync
Traceback (most recent call last):

  File "/usr/home/zach/venv/bin/xet", line 8, in <module>
    sys.exit(cli())

  File "/usr/home/zach/venv/lib/python3.9/site-packages/pyxet/cli.py", line 147, in sync
    cmd.validate()

  File "/usr/home/zach/venv/lib/python3.9/site-packages/pyxet/sync.py", line 34, in validate
    raise ValueError(f"Unsupported destination protocol: {self._dest_proto}, only xet:// targets are supported")

ValueError: Unsupported destination protocol: file, only xet:// targets are supported