fix: remove buffer when its empty when hijacking

lua/nvim-tree.lua

@@ -302,6 +302,11 @@ function M.open_on_directory()
   local buf = api.nvim_get_current_buf()
   local bufname = api.nvim_buf_get_name(buf)
   if vim.fn.isdirectory(bufname) ~= 1 then
+    if bufname == "" then
+      vim.schedule(function()
+        vim.api.nvim_buf_delete(buf, { force = true })
+      end)
+    end
     return
   end