fix(cli): rephrase not empty directory error message

[jamesgeorge007]

The user is greeted with the following message if he/she attempts to create a project in the current directory that is non-empty:-

Can't create . because there's already a non-empty directory . existing in path.

This PR aims at rephrasing the above message such that the directory name shows up instead.

[jamesgeorge007]

It would be nice to have a --force flag to override this behavior #556 (comment)
@clarkdo WDYT?

[clarkdo]

@jamesgeorge007 Sorry for the late reply, the --force idea looks good to me, but I think we can use another name which is more related to dir overridden.