conform: disable autoformat on save for specified filetypes (#694)

Provide a method to disable autoformat on save lsp fallback for
specified filetypes. By default disable for C/C++ as an example,
because it does not have a well standardized coding style.

Based on conform recipe:
https://github.com/stevearc/conform.nvim/blob/master/doc/recipes.md

README.md

@@ -140,8 +140,7 @@ This will install the tree plugin and add the command `:Neotree` for you. For mo
 In the file: `lua/custom/plugins/filetree.lua`, add:
 
 ```lua
--- Unless you are still migrating, remove the deprecated commands from v1.x
-vim.cmd([[ let g:neo_tree_remove_legacy_commands = 1 ]])
+-- File: lua/custom/plugins/filetree.lua
 
 return {
   "nvim-neo-tree/neo-tree.nvim",

init.lua

@@ -130,6 +130,9 @@ vim.opt.signcolumn = 'yes'
 
 -- Decrease update time
 vim.opt.updatetime = 250
+
+-- Decrease mapped sequence wait time
+-- Displays which-key popup sooner
 vim.opt.timeoutlen = 300
 
 -- Configure how new splits should be opened
@@ -436,6 +439,10 @@ require('lazy').setup({
       -- Useful status updates for LSP.
       -- NOTE: `opts = {}` is the same as calling `require('fidget').setup({})`
       { 'j-hui/fidget.nvim', opts = {} },
+
+      -- `neodev` configures Lua LSP for your Neovim config, runtime and plugins
+      -- used for completion, annotations and signatures of Neovim apis
+      { 'folke/neodev.nvim', opts = {} },
     },
     config = function()
       -- Brief Aside: **What is LSP?**
@@ -482,7 +489,7 @@ require('lazy').setup({
 
           -- Jump to the definition of the word under your cursor.
           --  This is where a variable was first declared, or where a function is defined, etc.
-          --  To jump back, press <C-T>.
+          --  To jump back, press <C-t>.
           map('gd', require('telescope.builtin').lsp_definitions, '[G]oto [D]efinition')
 
           -- Find references for the word under your cursor.
@@ -575,18 +582,6 @@ require('lazy').setup({
           -- capabilities = {},
           settings = {
             Lua = {
-              runtime = { version = 'LuaJIT' },
-              workspace = {
-                checkThirdParty = false,
-                -- Tells lua_ls where to find all the Lua files that you have loaded
-                -- for your neovim configuration.
-                library = {
-                  '${3rd}/luv/library',
-                  unpack(vim.api.nvim_get_runtime_file('', true)),
-                },
-                -- If lua_ls is really slow on your computer, you can try this instead:
-                -- library = { vim.env.VIMRUNTIME },
-              },
               completion = {
                 callSnippet = 'Replace',
               },
@@ -637,10 +632,16 @@ require('lazy').setup({
     'stevearc/conform.nvim',
     opts = {
       notify_on_error = false,
-      format_on_save = {
+      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 }
+        return {
           timeout_ms = 500,
-        lsp_fallback = true,
-      },
+          lsp_fallback = not disable_filetypes[vim.bo[bufnr].filetype],
+        }
+      end,
       formatters_by_ft = {
         lua = { 'stylua' },
         -- Conform can also run multiple formatters sequentially
@@ -676,6 +677,17 @@ require('lazy').setup({
           end
           return 'make install_jsregexp'
         end)(),
+        dependencies = {
+          -- `friendly-snippets` contains a variety of premade snippets.
+          --    See the README about individual language/framework/plugin snippets:
+          --    https://github.com/rafamadriz/friendly-snippets
+          -- {
+          --   'rafamadriz/friendly-snippets',
+          --   config = function()
+          --     require('luasnip.loaders.from_vscode').lazy_load()
+          --   end,
+          -- },
+        },
       },
       'saadparwaiz1/cmp_luasnip',
 
@@ -718,6 +730,10 @@ require('lazy').setup({
           -- Select the [p]revious item
           ['<C-p>'] = cmp.mapping.select_prev_item(),
 
+          -- scroll the documentation window [b]ack / [f]orward
+          ['<C-b>'] = cmp.mapping.scroll_docs(-4),
+          ['<C-f>'] = cmp.mapping.scroll_docs(4),
+
           -- Accept ([y]es) the completion.
           --  This will auto-import if your LSP supports it.
           --  This will expand snippets if the LSP sent a snippet.
@@ -746,6 +762,9 @@ require('lazy').setup({
               luasnip.jump(-1)
             end
           end, { 'i', 's' }),
+
+          -- For more advanced luasnip keymaps (e.g. selecting choice nodes, expansion) see:
+          --    https://github.com/L3MON4D3/LuaSnip?tab=readme-ov-file#keymaps
         },
         sources = {
           { name = 'nvim_lsp' },
@@ -822,17 +841,24 @@ require('lazy').setup({
   { -- Highlight, edit, and navigate code
     'nvim-treesitter/nvim-treesitter',
     build = ':TSUpdate',
-    config = function()
-      -- [[ Configure Treesitter ]] See `:help nvim-treesitter`
-
-      ---@diagnostic disable-next-line: missing-fields
-      require('nvim-treesitter.configs').setup {
+    opts = {
       ensure_installed = { 'bash', 'c', 'html', 'lua', 'markdown', 'vim', 'vimdoc' },
       -- Autoinstall languages that are not installed
       auto_install = true,
-        highlight = { enable = true },
-        indent = { enable = true },
-      }
+      highlight = {
+        enable = true,
+        -- Some languages depend on vim's regex highlighting system (such as Ruby) for indent rules.
+        --  If you are experiencing weird indenting issues, add the language to
+        --  the list of additional_vim_regex_highlighting and disabled languages for indent.
+        additional_vim_regex_highlighting = { 'ruby' },
+      },
+      indent = { enable = true, disable = { 'ruby' } },
+    },
+    config = function(_, opts)
+      -- [[ Configure Treesitter ]] See `:help nvim-treesitter`
+
+      ---@diagnostic disable-next-line: missing-fields
+      require('nvim-treesitter.configs').setup(opts)
 
       -- There are additional nvim-treesitter modules that you can use to interact
       -- with nvim-treesitter. You should go explore a few and see what interests you: