feat(nvim): Code completion and Snippets.

Add nvim-cmp to code completion.

Reference: [Autocomplete and Snippets in Neovim | FREE COURSE // EP 5](https://youtu.be/iXIwm4mCpuc?si=eEz9muJrw-AjX_ge)

Author: paulopatto

nvim/lua/plugins/completions.lua

@@ -0,0 +1,47 @@
+return {
+  {
+    "hrsh7th/cmp-nvim-lsp"
+  },
+  {
+    'L3MON4D3/LuaSnip',
+    dependencies = {
+      'saadparwaiz1/cmp_luasnip',
+      'rafamadriz/friendly-snippets'
+    },
+  },
+  {
+    "hrsh7th/nvim-cmp",
+    dependencies = { 'hrsh7th/cmp-nvim-lsp' },
+    config = function()
+      -- Set up nvim-cmp.
+      local cmp = require'cmp'
+      require("luasnip.loaders.from_vscode").lazy_load()
+
+      cmp.setup({
+        snippet = {
+          -- REQUIRED - you must specify a snippet engine
+          expand = function(args)
+            require('luasnip').lsp_expand(args.body) -- For `luasnip` users.
+          end,
+        },
+        window = {
+          completion = cmp.config.window.bordered(),
+          documentation = cmp.config.window.bordered(),
+        },
+        mapping = cmp.mapping.preset.insert({
+          ['<C-b>']     = cmp.mapping.scroll_docs(-4),
+          ['<C-f>']     = cmp.mapping.scroll_docs(4),
+          ['<C-Space>'] = cmp.mapping.complete(),
+          ['<C-e>']     = cmp.mapping.abort(),
+          ['<CR>']      = cmp.mapping.confirm({ select = true }),
+        }),
+        sources = cmp.config.sources({
+          { name = 'nvim_lsp' },
+          { name = 'luasnip' }, -- For luasnip users.
+        }, {
+            { name = 'buffer' },
+          })
+      })
+    end,
+  }
+}

nvim/lua/plugins/lsp.lua

@@ -24,10 +24,17 @@ return {
   {
     "neovim/nvim-lspconfig",
     config = function()
+      local capabilities = require('cmp_nvim_lsp').default_capabilities()
       local lspconfig = require("lspconfig")
-      lspconfig.lua_ls.setup({})
-      lspconfig.tsserver.setup({})
-      lspconfig.pyright.setup({})
+      lspconfig.lua_ls.setup({
+        capabilities = capabilities
+      })
+      lspconfig.tsserver.setup({
+        capabilities = capabilities
+      })
+      lspconfig.pyright.setup({
+        capabilities = capabilities
+      })
 
       -- Buffer local mappings.
       -- See `:help vim.lsp.*` for documentation on any of the below functions