Provide a warning and remediation suggestion when NO secret patterns are defined

This tool is useful, but because patterns need to be defined in the repo it would be nice if the tool alerted the end-user when NO secret patterns are defined since this can lead to false positives, simply because someone missed a setup step that is detectable.

No files, tests, or entry points are named. Begin by locating where repository secret patterns are loaded, then determine how to detect that none are defined and where a user-facing warning can be emitted; done means the warning includes a remediation suggestion for the missing setup.

Written by the indexing model from the issue text.