api render sub object attributes on the same level as the parent's attributes

Hi,
I try to export activity data through API : /api/index.php?uri=Activity/all
and I get 2 fixPlanning attributes on the same json object : 1 for Activity and 1 for ActivityPlanningElement element
This is not json friendly and value may override.
I suggest modifying /api/index.php:350 at least withif ($res!="") { $res.=", "{$fld}":{";}$res.=jsonDumpObj($val, true);if ($res!="") { $res.="} ";}
It's probably not enough as it could also be an array that need a loop

best regards,
Laurent