diagnostic.settings usage

[marvin-tr-81]

Hi, I am trying to setup diagnostic icons in nixvim, I have come across this post online but couldn't translate it to nix: https://vi.stackexchange.com/questions/45312/how-do-i-change-characters-used-nvim-diagnostics-signs

vim.diagnostic.config({
    
    underline = false,
    signs = { 
        active = true,
        text = {
          [vim.diagnostic.severity.ERROR] = "",
          [vim.diagnostic.severity.WARN]  = "",
          [vim.diagnostic.severity.HINT]  = "󰟃",
          [vim.diagnostic.severity.INFO]  = "",
        },
    },
    virtual_text = false,
    float = {
        border = "single",
        format = function(diagnostic)
            return string.format(
                "%s (%s) [%s]",
                diagnostic.message,
                diagnostic.source,
                diagnostic.code or diagnostic.user_data.lsp.code
            )
        end,
    },
})

I know it should go in

diagnostic.settings = {
...
}

but couldn't make it work.

I have also found this post but it didn't work for me: #3398

Some help would be much appreciated. Thanks a lot.