FEATURE: Allow NeoTreeWinSeparator to be Positioned on the Left When `position = "right"`

[hungvx-dev]

Did you check the docs?

• I have read all the docs.

Is your feature request related to a problem? Please describe.

When NeoTree is configured with window.position = "right", the NeoTreeWinSeparator highlight applies to the separator on the right side of the NeoTree window (between NeoTree and the main buffer). Since the NeoTree window is at the right edge of the Neovim screen, this separator is either invisible or has no effect. This makes it impossible to visually distinguish the NeoTree window from the main buffer using a highlighted separator on its left side.

Describe the solution you'd like.

I would like an option to configure the separator (highlighted by NeoTreeWinSeparator) to appear on the left side of the NeoTree window when window.position = "right". For example, a new configuration option like window.separator_position could be added:

require("neo-tree").setup({
  window = {
    position = "right",
    separator_position = "left", -- Place separator on the left
  },
})

This would allow the separator to be visible between the NeoTree window and the main buffer, with the NeoTreeWinSeparator highlight applied correctly.

Describe alternatives you've considered.

No response

Additional Context

No response

[pynappo]

this is just how winseparator works in neovim, it only applies to the right border of the window: neovim/neovim#24266

although this could be hacked around like in https://github.com/nvim-zh/colorful-winsep.nvim where you just draw a window ontop of each of the window's borders