? key for showing help or all aerial keymappings

[qvieth]

There are keybindings like o to fold or zM to fold all tree. But remembering or go to the docs for each time the user forget is not so inconvenient.

Please consider adding the feature "press ? key to show all the keybindings or help."

Also, many thanks for making this plugin.

[stevearc]

Yep, that's a good idea! I'll do this in the near-ish future