Unwanted margin along neo-tree edge

[ryanmsnyder]

How can I get rid of this small margin along neo-tree?

Here's a screenshot of how I want it to look using NvimTree:

[ryanmsnyder]

I resolved this issue by setting the following fillchars:

vim.opt.fillchars = {
  vert = "▏",
  horiz = "▁",
}