Update refs.mdx

src/routes/concepts/refs.mdx

@@ -79,14 +79,14 @@ This is useful when you want to access the element directly, but the element may
 ```jsx
 function App() {
 	const [show, setShow] = createSignal(false)
-	const [element, setElement] = createSignal()
+	let element!: HTMLParagraphElement
 
 	return (
 		<div>
 			<button onClick={() => setShow((isShown) => !isShown)}>Toggle</button>
 
 			<Show when={show()}>
-				<p ref={setElement}>This is the ref element</p>
+				<p ref={element}>This is the ref element</p>
 			</Show>
 		</div>
 	)