fix: Implicit current buf on centralize selection

[thedaviddelta]

The recent implementation change to center the selected file produces a very odd error on my setup.
If I have nvim-tree open (for example, when opening an empty project) and then open a file using any other mean (e.g. Telescope) a Invalid buffer id: 1 error pops into my neovim.
Tweaking the code I've discovered the cause: the centralize_selection autocmd that runs when closing the tree tries to reads the bufnr of Telescope and then schedules the zz call, running after some milliseconds when the Telescope buffer is already killed.
By implicitly using the current buffer (by using 0 as a param) instead of explicitly retrieving it solves this problem. It'd probably also work if the retrieving is moved inside the schedule function, but haven't tried as I don't think it's better to do so.

[gegoune]

0 is probably good here but maybe using buffer number from event object will be more robust?

[thedaviddelta]

Changed. I think it's also working correctly this way.

[gegoune]

Thanks, that's not exactly what I had in mind. Apologies for not being clear. I have requested changes with more detail.

[thedaviddelta]

This produces the same problem, as the event is populated before the schedule starts.
We should just use 0, or simply query the id inside the schedule callback.

[gegoune]

Didn't test it properly then. Schedule it then. Maybe Alex will have better solution.

[thedaviddelta]

Should I revert to the explicit or the implicit implementation?

[gegoune]

If 0 in scheduled context works then it seems like the easiest solution avoiding extra call to api.

[alex-courtis]

Gentle nudge for re-review @gegoune