feat(nut): add tab.tablist

[MunifTanjim]

local nut = {
  buf = {
    tablist = require("nougat.nut.tab.tablist"),
  },
}

tal:add_item(nut.tab.tablist.create({
  config = {
    active_tab = nut.tab.tablist.TabItem({
      hl = { bg = "purple", fg = "white" },
      prefix = " ",
      sep_left = sep.left_lower_triangle_solid(false),
      sep_right = sep.right_lower_triangle_solid(false),
      suffix = " ",
      config = { close = "" },
    }),
    inactive_tab = nut.tab.tablist.TabItem({
      hl = { bg = "fg", fg = "bg" },
      prefix = " ",
      sep_left = sep.left_lower_triangle_solid(false),
      sep_right = sep.right_lower_triangle_solid(false),
      suffix = " ",
      config = { close = "" },
    }),
  },
}))