make exa --tree more usable with symlinks

[Janik-Haag]

Currently I have exa --git --tree --icons as a alias for tree. And that works great with normal folders, but when working with symlinked folders tree ./result displays ./result -> /nix/store/rgckxqbb8asdyj0l66i6jrhwzqriahdf-labctl-0.0.15 and when doing tree ./result/ it displays what I actually want displayed:

./result
├──  bin
│  └──  labctl
└──  share
   ├──  bash-completion
   │  └──  completions
   │     └──  labctl.bash
   └──  zsh
      └──  site-functions
         └──  _labctl

I think that behavior makes sense when using exa like ls, but fell like there should be a edgecase for the --tree flag.

[ariasuni]

Closing this in favor of #393