make examples more consistent

Author: Rich-Harris

content/tutorial/01-svelte/02-reactivity/02-reactive-declarations/app-a/src/lib/App.svelte

@@ -2,12 +2,12 @@
 	let count = 0;
 	$: doubled = count * 2;
 
-	function handleClick() {
+	function increment() {
 		count += 1;
 	}
 </script>
 
-<button on:click={handleClick}>
+<button on:click={increment}>
 	Clicked {count}
 	{count === 1 ? 'time' : 'times'}
 </button>