Fix type for option relativenumber

"relativenumber" should be window local option, not buffer local option.

lua/custom-autocmd.lua

@@ -261,7 +261,7 @@ api.nvim_create_autocmd("BufReadPre", {
     if fn.getfsize(f) > file_size_limit or fn.getfsize(f) == -2 then
       vim.o.eventignore = "all"
       --  turning off relative number helps a lot
-      vim.bo.relativenumber = false
+      vim.wo.relativenumber = false
 
       vim.bo.swapfile = false
       vim.bo.bufhidden = "unload"