Fixing error with from() parameters in example

The from method requires $from and the $alias to be separate parameters.

    public function from($from, $alias, $indexBy = null);

The examples show: from('User u')

docs/en/reference/query-builder.rst

@@ -216,7 +216,7 @@ allowed. Binding parameters can simply be achieved as follows:
     // $qb instanceof QueryBuilder
 
     $qb->select('u')
-       ->from('User u')
+       ->from('User', 'u')
        ->where('u.id = ?1')
        ->orderBy('u.name', 'ASC')
        ->setParameter(1, 100); // Sets ?1 to 100, and thus we will fetch a user with u.id = 100
@@ -230,7 +230,7 @@ alternative syntax is available:
     // $qb instanceof QueryBuilder
 
     $qb->select('u')
-       ->from('User u')
+       ->from('User', 'u')
        ->where('u.id = :identifier')
        ->orderBy('u.name', 'ASC')
        ->setParameter('identifier', 100); // Sets :identifier to 100, and thus we will fetch a user with u.id = 100