Revert persistent undo and swap file disable stuff

This reverts commit 565f7c71dc.

Revert "add persistent undo functionality to both neovim and vim"

This reverts commit 1d8df9d310.

nvim/.config/nvim/init.lua

@@ -74,16 +74,6 @@ vim.cmd [[
     set errorformat^=[----]\ %f:%l:\ %m
 ]]
 
-vim.o.backup = false
-vim.o.writebackup = false
-vim.o.swapfile = false
-vim.o.autoread = true
-vim.o.undofile = true
-vim.o.undodir = vim.fn.expand("~/.vim/neoundodir")
-if vim.fn.isdirectory(vim.o.undodir) == 0 then
-  vim.fn.mkdir(vim.o.undodir, "p")
-end
-
 vim.keymap.set('n', ',cf', function()
     local qf = vim.fn.getqflist()
     for i, item in ipairs(qf) do