decide whether target path is determined by source namespace or by source path

[daslu]

Recently, the source of truth for the target path was changed from the source namespace to the source path.

This little breaking change has brought up a discussion of what would actually be better.

Zulip discussion:
https://clojurians.zulipchat.com/#narrow/channel/422115-clay-dev/topic/target.20path.20and.20files/