add extensions for autocomplete, autoclose, clipboard

lua/custom/plugins/cmp-npm.lua

@@ -0,0 +1,12 @@
+return {
+	'David-Kunz/cmp-npm',
+	config = function()
+		require('cmp-npm').setup()
+		local cmp = require('cmp')
+		local config = cmp.get_config()
+		table.insert(config.sources, {
+			name = 'npm', keyword_length = 4
+		})
+		cmp.setup(config)
+	end
+}