fix(keymaps): change v mode to x mode for save file (#1262)

While trying to disable `<C-s>` entirely by `vim.keymap.del({ "i", "v","n", "s" }, "<C-s>")`
in my own `keymaps.lua`, I got an error on reopening Neovim `No such mapping`.
After tinkering around a bit, I changed `v` to `x`, since `v` incorporates both
`x` and `s` and the error stopped occuring.

lua/lazyvim/config/keymaps.lua

@@ -80,7 +80,7 @@ map("i", ".", ".<c-g>u")
 map("i", ";", ";<c-g>u")
 
 -- save file
-map({ "i", "v", "n", "s" }, "<C-s>", "<cmd>w<cr><esc>", { desc = "Save file" })
+map({ "i", "x", "n", "s" }, "<C-s>", "<cmd>w<cr><esc>", { desc = "Save file" })
 
 --keywordprg
 map("n", "<leader>K", "<cmd>norm! K<cr>", { desc = "Keywordprg" })