Address some feedback around naming and (indirectly) m.key, optimize m.use

`m.use` is specially designed to be used a fair amount, and simulating it is relatively slow, so it's worth making a built-in.

`m.key` -> `m.keyed` provides for a simpler interface, one that you don't have to type `key` out explicitly for anymore. (Most frameworks require you to explicitly add a "key" attribute, while this approaches it more like a glorified `Map`.)

Author: dead-claudia

performance/components/shuffled-keyed-tree.js

@@ -17,9 +17,5 @@ function shuffle() {
 
 export const shuffledKeyedTree = () => {
 	shuffle()
-	var vnodes = []
-	for (const key of keys) {
-		vnodes.push(m.key(key, m("div.item")))
-	}
-	return vnodes
+	return m.keyed(keys, (key) => [key, m("div.item")])
 }