Provide interface to customize the comparing function between two nodes

[alex-courtis]

Discussed in https://github.com/nvim-tree/nvim-tree.lua/discussions/2727

^{Originally posted by rennsax March 27, 2024}
We can use the option sort.sorter to customize how the files are sorted. If a function is provided, the argument is a table of all nodes. After sorted by the user's function, nvim-tree still needs to perform merge sort on the result.

I just found the interface is too complex to customize (not to mention the performance issue) when I was trying to tweak nvim-tree to put some special files (like CMakeLists.txt) at the end.

Firstly, the interface can be more elegant if it just requires a function that compare two nodes with necessary information and return a boolean value indicating which one should precede. And the implementation of this function will be much more clear.

Secondly, I suggest that nvim-tree/explorer/sorts.lua could export some function utility for file sorting to ease the complexity of writing the comparing logic from scratch.

Is this a better design?

[alex-courtis]

That sounds reasonable. Please:

1. Sketch out the API here, maybe with some examples
2. Create a PR to build it