Trying to get property of non-object of type TValue

$contentNodes is type DOMNodeList

thank you!

1/ adding DOMNamedNodeMap generic annotation
2/ adding tests
3/ handling the TValue template type argument to not confuse property analysis

when fixed, I see there is no ->name nor ->value

it should be

    $name = $attr->nodeName;
    $value = $attr->nodeValue;

The next update will check this