* Moved `source.Files` to its own package, thus the type is now `files.Files`.
* Moved much of the location functionality from pkg `source` to its own package `location`.
* go1.21: changes to support slog as part of stdlib
* Removed accidentially checked-in line of code
* Fixed minor linting issues; reenable typecheck
* go1.21: switched to stdlib slices pkg
* CSV now renames duplicate ingest headers
* Fix broken test
* xlsx ingester now handles duplicate col names
* Update CHANGELOG
* Additional tests for ingest.column.rename
* Removed dead comment in grammar