* feat: add `shorten_len` option for path shortening
- adds option to configure the length of shortened parts of filenames
- only affects paths when "shorten" is in `path_display`
* chore: revert rebase for `path.lua` to 876bed9
* refactor: replace `shorten_len` with the `shorten` key in `path_display`
- also deprecates `utils.path_shorten` and passes straight to `plenary`s `Path:shorten`
* feat: allow `path_display` to handle table keys, as well as strings