fix: handle no filename comeing through from defsec

[owenrumney]

• fix: fix panic with single file location
• fix: catch results where the filename is not specified

[knqyf263]

@owenrumney Please squash and merge next time. Or, do you want me to merge PRs?

[owenrumney]

I don't understand. It's a one commit pr

[knqyf263]

Oh, I see. I'm sorry for the lack of explanation. GitHub has "Squash and merge" button. https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/incorporating-changes-from-a-pull-request/merging-a-pull-request

[knqyf263]