Restructure mode conponent

lua/lualine/components/mode.lua

@@ -1,8 +1,7 @@
 -- Copyright (c) 2020-2021 hoob3rt
 -- MIT license, see LICENSE for more details.
 
-local function mode()
-  local mode_map = {
+local mode_map = {
   ['n']    = 'NORMAL',
   ['no']   = 'O-PENDING',
   ['nov']  = 'O-PENDING',
@@ -32,13 +31,11 @@ local function mode()
   ['r?']   = 'CONFIRM',
   ['!']    = 'SHELL',
   ['t']    = 'TERMINAL',
-  }
-  local function get_mode()
+}
+local function mode()
   local mode_code = vim.api.nvim_get_mode().mode
   if mode_map[mode_code] == nil then return mode_code end
   return mode_map[mode_code]
-  end
-  return get_mode()
 end
 
 return mode