nvim: statusline: Do not set winbar for empty filename

nvim/.config/nvim/after/plugin/statusline.lua

@@ -297,7 +297,9 @@ api.nvim_create_autocmd({"BufWinEnter", "BufFilePost"}, {
     -- `:.` Reduces file name to be relative to current directory, if possible.
     local winbar_file = vim.fn.expand('%:.')
 
+    if winbar_file ~= '' then
       vim.opt_local.winbar = string.format(" %s%s", "%#WinbarFile#", winbar_file)
+    end
   end,
 })
 api.nvim_create_autocmd({"TermOpen", "TermEnter"}, {