Display indentation in lualine

[aquaherd]

local indent = {
    function()
        local style = vim.bo.expandtab and "Spaces" or "Tab Size"
        local size = vim.bo.expandtab and vim.bo.tabstop or vim.bo.shiftwidth
        return style .. ": " .. size
    end,
    cond = function()
        return vim.bo.filetype ~= ""
    end,
}

-- in your lualine section
-- ...
sections = {
    -- ...
    lualine_x = { indent, 'encoding', 'fileformat', 'filetype' },
    -- ...
},

-- ...