docs: input should grab the input slot (#125)

The Input component has a comment saying it should pull in the "label" slot but it really should pull in the "input" slot.

exercises/04.slots/01.problem.context/slots.tsx

@@ -14,6 +14,6 @@ export function Label(props: React.ComponentProps<'label'>) {
 }
 
 export function Input(props: React.ComponentProps<'input'>) {
- // 🐨 get the props from useSlotProps for a slot called "label" and apply those to the input
+ // 🐨 get the props from useSlotProps for a slot called "input" and apply those to the input
  return <input {...props} />
 }