overview.md: update to reflect new SelectedFiles behaviour
overview.md: update to reflect new SelectedFiles behaviour

artefactual-labs/appraisal-tab,djpillen/appraisal-tab,eckardm/appraisal-tab,artefactual-labs/appraisal-tab,eckardm/appraisal-tab,djpillen/appraisal-tab