docs: Set page anchor name for groupby

Author: ntucker

docs/rest/api/Query.md

@@ -98,7 +98,7 @@ render(<UsersPage />);
 
 </HooksPlayground>
 
-### Rearranging data with groupBy aggregations
+### Rearranging data with groupBy aggregations {#groupby}
 
 <HooksPlayground>
 
@@ -198,7 +198,7 @@ function TodosPage() {
   if (!todosByUser) return <div>Todos not found</div>;
   return (
     <div>
-      {Object.keys(todosByUser).map(userId => (
+      {Object.keys(todosByUser).slice(5).map(userId => (
         <TodoByUser
           key={userId}
           userId={userId}