fix!: goto parent dir default key to <C-b>/b

[fdschmidt93]

As per reddit comment and hoping that people vote :).

I'm leaning towards <C-b>/b as that allows for the insert/normal mode mirroring of other keymaps rather than - (e.g. nvim-tree.lua default), since <C--> is not a recognized keycode.

Please hit an emoji on this PR with

Emoji	Insert/normal mode mapping
Rocket	<C-b>/b
Hooray	-/-

while keeping mapping convention at least somewhat in mind and that classic file tree's don't have to distinguish between insert and normal mode all too much I guess :)

For the time being I personally favor b.

Rules to break my decision:

• 10+ participants
• ~60% in favor of -

I'll let this run I guess for a couple of days.

Thanks!

[tjdevries]

I use - :)

[ChadCapra]

I use tmux default bindings so <C-b> prefix will conflict for me, but thank you for the awesome plugin!