Change format_on_save to a whitelist instead of a blacklist

Author: oriori1703

init.lua

@@ -686,14 +686,15 @@ require('lazy').setup({
     opts = {
       notify_on_error = false,
       format_on_save = function(bufnr)
-        -- Disable "format_on_save lsp_fallback" for languages that don't
-        -- have a well standardized coding style. You can add additional
-        -- languages here or re-enable it for the disabled ones.
-        local disable_filetypes = { c = true, cpp = true }
-        if disable_filetypes[vim.bo[bufnr].filetype] then
-          return nil
-        else
+        -- You can specify filetypes to autoformat on save here:
+        local enabled_filetypes = {
+          -- lua = true,
+          -- python = true,
+        }
+        if enabled_filetypes[vim.bo[bufnr].filetype] then
           return { timeout_ms = 500 }
+        else
+          return nil
         end
       end,
       default_format_opts = {