Add completedTasks to complex state mgmt (#699)

Co-authored-by: Atila Fassina <atila@fassina.eu>

src/routes/guides/complex-state-management.mdx

@@ -13,6 +13,7 @@ import { For, createSignal, Show, createMemo } from "solid-js"
 const App = () => {
 	const [tasks, setTasks] = createSignal([])
 	const [numberOfTasks, setNumberOfTasks] = createSignal(tasks.length)
+        const completedTasks = createMemo(() => tasks().filter((task) => task.completed))
 	let input
 
 	const addTask = (text) => {