chore: move plugins to an upper level

lua/config/plugins/ui/whichkey.lua

@@ -1,25 +0,0 @@
-local M = {
-  "folke/which-key.nvim",
-  event = "VeryLazy",
-  init = function()
-    vim.o.timeout = true
-    vim.o.timeoutlen = 500
-  end,
-}
-
-M.config = function()
-  require("which-key").setup({
-    win = {
-      border = "single",
-    },
-    plugins = {
-      marks = true,
-      registers = true,
-      spelling = {
-        enabled = false,
-      },
-    },
-  })
-end
-
-return M