For new checks and feature suggestions

• https://www.shellcheck.net/ (i.e. the latest commit) currently gives no useful warnings about this
• I searched through https://github.com/koalaman/shellcheck/issues and didn't find anything related

Here's a snippet or screenshot that shows the problem:

As documented here: CircleCI-Public/shellcheck-orb#34. Shellcheck was firing and returning a 0 exits status, but not all files were matched and it was difficult to debug which files that shellcheck was processing.

I'm proposing adding a --verbose flag to the shellcheck CLI and I would like it to emit the names of files that it evaluates.

BTW, thanks a ton for this project. I'm loving it :)