* Add fern extension
Fern[^1] is general purpose tree view that can browse and manipulate
file trees. This extension provides a simple and useful statusline for
fern buffers.
[^1]: https://github.com/lambdalisue/fern.vim
* Reuse nerdtree code for fern
* doc: mention fern in README
Co-authored-by: shadmansaleh <13149513+shadmansaleh@users.noreply.github.com>
Mark Story