chore(nvim): simplify imports and clean up plugin files

nvim/after/plugin/sad.lua

@@ -1,10 +1,5 @@
 -- https://github.com/ray-x/sad.nvim
-local status_ok, sad = pcall(require, "sad")
-if not status_ok then
-	return
-end
-
-sad.setup({
+require("sad").setup({
 	diff = "delta", -- you can use `diff`, `diff-so-fancy`
 	ls_file = "fd", -- also git ls_file
 	exact = false, -- exact match