refactor(completions): Make nvim-cmp's config more idiomatic

lua/plugins/completions.lua

@@ -11,31 +11,35 @@ return {
 		"L3MON4D3/LuaSnip",
 		"saadparwaiz1/cmp_luasnip",
 	},
-	config = function()
+	opts = function()
 		local cmp = require("cmp")
 
-		cmp.setup({
+		return {
+			window = {
+				completion = cmp.config.window.bordered(),
+			},
 			snippet = {
 				expand = function(args)
 					require("luasnip").lsp_expand(args.body)
 				end,
 			},
-			window = {
+			sources = {
-				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-e>"] = cmp.mapping.abort(),
-				["<CR>"] = cmp.mapping.confirm({ select = false }),
-			}),
-			sources = cmp.config.sources({
 				{ name = "nvim_lsp", priority = 2 },
 				{ name = "luasnip",  priority = 1 },
 				{ name = "buffer" },
-			}),
+			},
-		})
+		}
+	end,
+	keys = {
+		{ "<C-b>", function() require("cmp").mapping.scroll_docs(-4) end },
+		{ "<C-f>", function() require("cmp").mapping.scroll_docs(4) end },
+		{ "<C-e>", function() require("cmp").mapping.abort() end },
+		{ "<CR>", function() require("cmp").mapping.confirm({ select = false }) end },
+	},
+	config = function(_, opts)
+		local cmp = require("cmp")
+
+		cmp.setup(opts)
 
 		vim.api.nvim_create_autocmd("BufRead", {
 			group = vim.api.nvim_create_augroup("CmpSourceCargo", { clear = true }),