small exercise updates (#373)

exercises/06.styling/03.problem.size-prop/README.mdx

@@ -15,3 +15,6 @@ In this step, try to make this API work:
 	small lightblue box
 </Box>
 ```
+
+- You'll need 📜
+  [TypeScript's intersection (&) operator](https://www.typescriptlang.org/docs/handbook/2/objects.html#intersection-types)

exercises/06.styling/03.problem.size-prop/index.tsx

@@ -6,8 +6,8 @@ export function Box({
 	style = {},
 	className = '',
 	// 🐨 add a size prop here
-	...otherProps // 🦺 union this with an object that has a size prop type here which is
-	// optional and one of "small", "medium", or "large"
+	...otherProps // 🦺 intersect (&) this with an object that has a size prop type here which is
+	// optional and is one of "small", "medium", or "large"
 }: React.ComponentProps<'div'>) {
 	// 🐨 based on the size prop, define a new variable called sizeClassName
 	return (

exercises/07.forms/01.problem.form/index.tsx

@@ -4,6 +4,7 @@ function App() {
 	// 🐨 render a form
 	//   🐨 render a "Username" label
 	//   🐨 render an input with the name "username"
+	//   🐨 render a button
 	// 💯 associate the label to the input using htmlFor and id attributes
 	// 💯 explicitly set the button type appropriately
 	return 'TODO'