Error if directory doesn't exist

[ghost]

Currently, searching a directory that doesn't exist will silently fail.

$ astpath -d /tmp/this-dir-doesnt-exist './/Try'

If a directory doesn't exist because I misspelled it, I'd like to get an error.

[spookylukey]

This is fixed in my fork - https://github.com/spookylukey/pyastgrep