fixing up docs

docs/step1-07/final/src/components/TodoFooter.tsx

@@ -7,12 +7,16 @@ interface TodoFooterProps {
 
 export const TodoFooter = (props: TodoFooterProps) => {
   const itemCount = Object.keys(props.todos).filter(id => !props.todos[id].completed).length;
+  const _onClick = () => {
+    props.clear();
+  };
+
   return (
     <footer>
       <span>
         {itemCount} item{itemCount > 1 ? 's' : ''} left
       </span>
-      <button onClick={() => props.clear()} className="submit">
+      <button onClick={_onClick} className="submit">
         Clear Completed
       </button>
     </footer>