moveUpNode method
Moves node
up in the children list.
Implementation
bool moveUpNode(DOMNode node) {
if (isEmptyContent) return false;
var idx = indexOfNodeIdenticalFirst(node);
if (idx < 0) return false;
if (idx == 0) return true;
_content!.removeAt(idx);
var idxUp = _contentFromIndexBackwardWhere(
idx - 1, 0, (node) => node is DOMElement);
if (idxUp < 0) {
idxUp = 0;
}
_content!.insert(idxUp, node);
node.parent = this;
return true;
}