Before this patch, a generic file does not exist is being shown, which is not useful enough.

We used to have a user-friendlier message in the past, but it probably was lost in the recent refactors.

Before:

$ task
file does not exist

After:

$ task
task: No Taskfile found at "/Users/andrey/Developer/repo" (or any of the parent directories). Run `task --init` to create a new Taskfile.