feat: [sort] add alphabetic descending and natural sorting

[SpotlightKid]

Natural sorting function implemented after http://notebook.kulchenko.com/algorithms/alphanumeric-natural-sorting-for-humans-in-lua (version four).

[adamharrison]

I like it! The only thing I can think of is that it may make sense to symlink sort:sort to sort:sort-alpha; just so that it continues to work for people that've bound this to a key already; though this isn't critical (I can't imagine too many people have this on hotkey).

[SpotlightKid]

Yes, I thought about that too. So would you suggest simply binding function() do_sort(sort_alpha) end to ["sort:sort"] as well as ["sort:sort-alpha"]?

[adamharrison]

That makes sense to me.

[SpotlightKid]

Closing this since I'm cleaning up my unmerged/unfinisged PRs and this is now conflicting and I don't use lite-xl anymore.