feature request: allow multiple filter_relations

basically allow:
```
$[?(
  @.a == 1 || @.a == 2 || @.a == 3
)]
```
instead of 
```
$[?(
  (@.a == 1 || @.a == 2) || @.a == 3
)]
```
unfortunately no-one else implements this AFAIK, so feel free to close if it doesn't make sense