feat: have preview open left of nvim-tree if view.side == 'right'

[richardso21]

I personally have nvim-tree open at the right side, so the previous floating preview would block items below the current node being hovered. Here's an example (the preview hides the rest of the items in the project directory):

Instead, if config.view.side == 'right' (config deriving from the setup configs from nvim-tree, not this plugin), I calculate the col window offset differently so that the preview won't get in the way:

Let me know what you think!