[bug] signs are white with nvim-gruvbox

[werdahias]

Nvim: 0.9.5
nvim-gruvbox: https://github.com/ellisonleao/gruvbox.nvim

This is solely related to gruvbox; disabling the colorscheme gets me colored signs in the sign column again.

:highlight GitGutterAdd:
GitGutterAdd   xxx links to GitGutterAddDefault

:highlight SignColumn
SignColumn     xxx guibg=#3c3836
                   links to LineNr